MCQ 11 Mark
Which of the following statements is false?
AnswerCorrect option: A. Two different solutions of sucrose of the same molality prepared in different solvents will have the same depression in the freezing point.
- Two different solutions of sucrose of same molality prepared in different solvents will have the same depression in freezing point.
Explanation:
Tf = Kfm Since Kf values depend upon the nature of solvent, the depression in freezing point of the solution would not be the same.
View full question & answer→Question 21 Mark
The correct statement among the following is:
Answer
- Smoke is carbon dispersed in air.
Explanation:
Smoke is carbon (solid particle) dispersed in air. It is the type of solid in gas type of solution.
View full question & answer→Question 31 Mark
Two beakers of capacity 500mL were taken. One of these beakers, labelled as “A”, was filled with 400mL water whereas the beaker labelled “B” was filled with 400mL of 2M solution of NaCl. At the same temperature both the beakers were placed in closed containers of same material and same capacity as shown in. At a given temperature, which of the following statement is correct about the vapour pressure of pure water and that of NaCl solution.
Answer
- vapour pressure in container (A) is more than that in container (B).
Explanation:
Since NaCl is a non-volatile solute, it will reduce vapour pressure of the solution. Hence, vapour pressure of pure water in container A is more than in container B.
View full question & answer→Question 41 Mark
The rate of vapourisation of water depends upon:
Answer
- All of the above
Explanation:
The rate of vapourization of water depends on the temperature and surface area.
The kinetic energy of molecules depends on the temperature of the water.
Increasing temperature or surface area increases the rate of evaporation and vice-versa.
View full question & answer→Question 51 Mark
Out of molality (m), molarity (M), formality (F) and mole fraction (x), those which are independent of temperature are:
Question 61 Mark
The incorrect statement is:
Answer
- Vapour pressure only depends on temperature and not on the nature of substance.
Explanation:
The vapour pressure depends on the temperature and the nature of substance.
View full question & answer→Question 71 Mark
A solution of benzene and toluene is an example of ________ solution.
Answer
- Ideal
Explanation:
Due to absence of polarity, benzene and toluene dont have any interaction forces so they dont show any deviation and forms ideal solutions.
View full question & answer→Question 81 Mark
When a solution containing non - volatile solute is diluted with water,
Answer
- Its boiling point increases.
View full question & answer→Question 91 Mark
On the basis of information given below mark the correct option.
Information: On adding acetone to methanol some of the hydrogen bonds between methanol molecules break.
Answer
- At specific composition methanol-acetone mixture will form minimum boiling azeotrope and will show positive deviation from Raoult’s law.
Explanation:
At specific composition methanol-acetone mixture will show positive deviation from Raoulfs law as it has lesser interactions than methanol- methanol and acetone-acetone interactions. Hence it forms minimum boiling azeotrope.
View full question & answer→Question 101 Mark
Among the following substances the lowest vapour pressure is exerted by:
Question 111 Mark
The atmospheric pollution is generally measured in the units of:
Question 121 Mark
To determine the solubility of a solute in water, a solution must be prepared that is___________.
Answer
- Saturated
Explanation:
The maximum number of moles of solute that can be dissolved in a given volume of solution represents the solubility of solution.
A solution with the maximum possible amount of solute is saturated.
Hence a saturated solution must be prepared to determine the solubility of a solute in water,
View full question & answer→Question 131 Mark
What is an example of camphor in N2 gas?
Answer
- Solid in gas solution
Explanation:
Solid in gaseous solution is an example of camphor in N2 gas. Gaseous solution refers to a solution in which the solvent is gaseous. Other gaseous solutions include air (O2 + N2), iodine vapors in air, humidity in air, and so on.
View full question & answer→Question 141 Mark
$18g$ glucose $(C_6H_{12}O_6)$ is added to $178.2g$ of water. The vapour pressure of this aqueous solution at $100^0C$ in torr is:
AnswerMolecular mass of water $= (2 \times 1) + (1 \times 16) = 18g$
For $178.2g$ water, $\text{n}_\text{A}=\frac{178.2}{18}=9.9\text{mol}$
Molecular mass of glucose $= (6)(12) + (12)(1) + 6(16) = 180g.$
For $18g$ glucose, $\text{n}_\text{B}=\frac{18}{180}=0.1\text{mol}$
$\text{X}_{\text{B}}=\frac{0.1}{(0.1+9.9)}=0.01$
$\text{X}_{\text{A}}=1-0.01=0.99$
For lowering of vapour pressure,
$\text{P}=\text{P}^0_\text{A}\text{x}^{\text{A}}=\text{P}^0_\text{A}(1-\text{X}_\text{B})$
$\text{P}=760(1-0.01)$
$\text{P}=760-7.6$
$\text{P}=752.40\ \text{torr}$
Vapour pressure of water is $752.40 \ torr.$
View full question & answer→Question 151 Mark
When $1$ mole of a substance is present in $1L$ of the solution, it is known as $:$
AnswerMolar concentration is a measure of the concentration of a solute in a solution and its unit is mol $L^{−1}.$
Molarity is a method to express the concentration of a solution.
It is defined as the number of moles of solute dissolved per liter of solution.
Hence, when $1$ mole of a substance is present in $1L$ of the solution, it is known as a molar solution.
View full question & answer→Question 161 Mark
The molal elevation constant depends upon:
Question 171 Mark
In which case van't Hoff factor is maximum $($assuming no hydrolysis$)$?
AnswerSoluten $a\ i = [1 + (n -1)a] \text{KCl}\ 20.51.5$
$\ce{K_2SO_{4} 30.41.8}$
$\ce{FeCl_3 40.31.9}$
$\ce{SnCl_4 50.21.8}$
View full question & answer→Question 181 Mark
Colligative properties are observed when ___________.
Answer
- A non volatile solid is dissolved in a volatile liquid.
- A non volatile liquid is dissolved in another volatile liquid.
Explanation:
Colligative properties are observed when a non-volatile solid or liquid are dissolved in a volatile liquid.
View full question & answer→Question 191 Mark
Sprinkling of salt helps in clearing the snow covered roads in hills. The phenomenon involved in the process is:
Answer
- Depression in freezing point of snow.
View full question & answer→Question 201 Mark
Raoult's law is obeyed by each constituent of a binary liquid solution when:
Answer
- The forces of attractions between like molecules are identical with those between unlike molecules.
Explanation:
When the forces of attractions between like molecules are identical with those between unlike molecules, Raoult's law is obeyed by each constituent of a binary liquid solution.
In such case, the total vapour pressure of the solution is the sum of the partial vapour pressures of components of the solution.
View full question & answer→Question 211 Mark
The boiling point of an azeotropic mixture of water and ethanol is less than that of water and ethanol. The mixture shows:
Answer
- Positive deviation from Raoult’s Law.
View full question & answer→Question 221 Mark
A concentrated solution contains high amount of ________:
Answer
- Solute
Explanation:
A concentrated solution contains the maximum amount of solute that can be dissolved because solubility depends on temperature, a solution that is concentrated at one temperature may not be concentrated at a higher temperature.
View full question & answer→Question 231 Mark
The vapour pressure of a dilute solution of a solute is not influenced by:
Answer
- Melting point of solute
Explanation:
Vapour pressure of a dilute solution depends upon the temperature, mole fraction, and degree of dissociation of solute and independent of the melting point of solute.
View full question & answer→Question 241 Mark
People add sodium chloride to water while boiling eggs. This is to:
Answer
- Increase the boiling point.
View full question & answer→Question 251 Mark
Intermolecular forces between two benzene molecules are nearly of same strength as those between two toluene molecules. For a mixture of benzene and toluene, which of the following are not true?
Answer
- These will form minimum boiling azeotrope.
- These will not form ideal solution.
Explanation:
In a mixture of benzene and toluene intermolecular forces between benzene and toluene molecules would be nearly of the same strength as those of two benzene molecules and two toluene molecules separately. The solution will, therefore, form an ideal solution & obey Raoult’s law. So, the option (iii) & (iv) is not true.
View full question & answer→Question 261 Mark
In isotonic solutions ____________.
Answer
- Osmotic pressure is same.
- Solute and solvent may or may not be same.
Explanation:
For isotonic solutions osmotic pressure is same, solute or solvent may not be same.
View full question & answer→Question 271 Mark
Which of the following statements is false?
Answer
- In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
Explanation:
In reverse osmosis solvent molecules move through a semipermeable membrane from a region of higher concentration of solute to a region of lower concentration, therefore the given statement at (ii) is false.
View full question & answer→Question 281 Mark
The ratio of the actual value of a colligative property to the value calculated, assuming the substance to be a nonelectrolyte, is referred to as ..................
Answer
- The van't Hoff factor
Explanation:
The van't Hoff factor is the ratio of the actual value of a colligative property to the value calculated. It is assumed that the substance is a nonelectroyte.
It can also be represented as the ratio of actual number of particles to the number of particles for no ionization.
View full question & answer→Question 291 Mark
Which of the following fluoride is used as rat poison?
Question 301 Mark
Which one of the following is a primary standard?
AnswerThe primary standard is a compound of sufficient purity from which standard solutions of known normalities can be prepared by direct weighing of it and diluting to a defined volume of solution.
Potassium Dichromate $\ce{(K_2Cr_2O_7)}$ is suitable to be used as a primary standard. It cannot be obtained in very pure form. It readily reacts with any traces of organic material or any other reducing substance in wate
View full question & answer→Question 311 Mark
Isotonic solutions must have the same ___________.
Answer
- Elevation in boiling point.
- Depression in freezing point.
Explanation:
Two solutions which have the same osmotic pressure at a given temperature are said to be isotonic in nature. The osmotic pressure of a given solution is given by the formula
$\pi=\text{CRT}=\frac{\text{n}}{\text{VRT}}$
Where π is the osmotic pressure of the solution, C is the concentration, the moles of solute per volume of solvent and T is the temperature, with R being universal gas constant. Osmotic pressure is a colligative property, hence for two solutions to be isotonic, the nature of the solute does not matter, i.e. the solute in the two solutions do not have to be the same. Even the density, which does not have a place in the equation of osmotic pressure does not need to be the same. The isotonic solutions at a given temperature need to have the same volume and same molar concentration, hence they will also have the equal elevation in boiling point and depression in freezing point, two other colligative properties.
View full question & answer→Question 321 Mark
On dissolving sugar in water at room temperature solution feels cool to touch. Under which of the following cases dissolution of sugar will be most rapid?
Answer
- Powdered sugar in hot water.
Explanation:
Since the solution is cool to touch, the dissolution is endothermic. Therefore, high temperature will favour dissolution. Further, powdered sugar has large surface area and is favourable for dissolution.
View full question & answer→Question 331 Mark
Value of Henry’s constant $K_H ........$
AnswerValue of Henry’s constant increases with increase in temperature.
View full question & answer→Question 341 Mark
The following substances were all dissolved in 100 grams of water at 290K to produce saturated solutions.If the solution is heated to 310K, which substance will have a decrease in its solubility:
Answer
- HCI
Explanation:
The following substances were all dissolved in 100 grams of water at 290K to produce saturated solutions. If the solution is heated to 310K, HCl will have a decrease in its solubility. HCl is a gas. The solubility of a gas in a solution is inversely proportional to the absolute temperature. With increase in the temperature, the solubility of a gas decreases.
View full question & answer→Question 351 Mark
A cylinder filled with a movable piston contains liquid water in equilibrium with water vapour at 25oC. Which one of the following operations results in a decrease in the equilibrium vapour pressure?
Answer
- Dissolving salt in the water
Explanation:
Vapour pressure is a surface phenomenon, when the surface area is more, vapour pressure will be more. When we add solute, what we do is we decrease the vapour pressure of solvent because same of the salt ions will be present at the solvent surface, thus taking place of same of the solvent particles which were actively participating in maintain, that previous high value of vapour pressure. So, the equilibrium vapour pressure value decreases. Thus, dissolving salt in water results in decreasing of equilibrium vapour pressure.
View full question & answer→Question 361 Mark
The pressure that a single component in a gaseous mixture would exert if it existed alone in the same volume as the mixture and at the same temperature as the mixture is referred to as.
Answer
- Partial pressure
Explanation:
Partial pressure is the pressure exerted by a single component in a gaseous mixture if it exists alone in the same volume.
View full question & answer→Question 371 Mark
Consider the and mark the correct option.
Answer
- Water will move from side (B) to side (A) if a pressure greater than osmotic pressure is applied on piston (B).
Explanation:
Water will move from side (B) to side (A) if pressure greater than osmotic pressure is applied on piston (B) due to reverse osmosis.
View full question & answer→Question 381 Mark
Which of the following units is useful in relating concentration of solution with its vapour pressure?
AnswerIt is mole fraction $(x)$ which is useful in relating concentration of solution with its vapour pressure.
For example according to Rault's law in a binary solution of two volatile liquids, $p_1 = x_1 \ p^0{}_1$
where $p_1$ is vapour pressure of component $1,$ and $x_1$ is its mole fraction in solution, $p^0{}_1$ denotes the vapour pressure of pure solvent.
View full question & answer→Question 391 Mark
At equilibrium, the rate of dissolution of a solid solute in a volatile liquid solvent is:
Answer
- Equal to the rate of crytallisation
Explanation:
Crystallization is the process of the formation of solid crystals precipitating from a solution.
In an unsaturated solution, the rate of dissolution of a solute in a volatile liquid solvent is greater than the rate of crystallization.
In a supersaturated solution, the rate of dissolution of a solute in a volatile liquid solvent is less than the rate of crystallization.
At equilibrium, the rate of dissolution of a solute in a volatile liquid solvent is equal to the rate of crystallization.
View full question & answer→Question 401 Mark
Van’t Hoff factor i is given by the expression __________.
Answer
- $\text{i}=\frac{\text{Normal molar mass}}{\text{Abnormal molar mass}}$
- $\text{i}=\frac{\text{Observed colligative property}}{\text{Calculated colligative property}}$
View full question & answer→Question 411 Mark
Which salt may show the same value of van't Hoff factor $(i)$ as that of $\ce{K_4Fe(CN)_6}$ in very dilute solution state?
Answer$Al_2(SO_4)_{3}$
View full question & answer→Question 421 Mark
$1$ mole of liquid $A$ and $9$ moles of liquid $B$ are mixed to form a solution. If $\text{P}^\circ_\text{B}=400_\text{ mm}$ of $Hg$ and $\text{P}^\circ_\text{B}=200_\text{ mm}$ of $Hg$ at a temperature $'T\ '$ and normal boiling point of liquid $B$ is $300K$ then answer the questions that follow.
Given data: $K_b = 2.7K kg$ mol$^{−1},$ Molar mass of $B = 100$
If $'A\ '$ is perfectly non$-$volatile and it dimerises to an extent of $60\%$ then what will be the vapour pressure of the solution.
Answer$\frac{3600}{9.7}\text{ mm}\ \text{of}\ \text{ Hg}$
View full question & answer→Question 431 Mark
An unripe mango placed in a concentrated salt solution to prepare pickle, shrivels because ___________.
Answer
- It loses water due to osmosis.
Explanation:
Water starts moving out of mango (lower concentration) to the salt solution (higher concentration) due to osmosis.
View full question & answer→Question 441 Mark
$4L$ of $0.02M$ aqueous solution of $\text{NaCl}$ was diluted by adding one litre of water. The molality of the resultant solution is $.......$
AnswerApply the relation$, M_1V_1 = M_2V_2$
Given$, M_{1 }= 0.02M, V_{1 }= 4L, M_{2 }= ?, V_{2 }= 5L$
Therefore$, 0.02 \times 4L = M_{2 }\times 5L$
$M_{2 }= 0.08/5$
$=0.016M$
View full question & answer→Question 451 Mark
Low concentration of oxygen in the blood and tissues of people living at high altitude is due to ____________.
Answer
- Low atmospheric pressure.
Explanation:
At high altitude the atmospheric pressure is decreased &, due to low atmospheric pressure the solubility of oxygen in blood and tissues is reduced.
View full question & answer→Question 461 Mark
What happens when a solute crystal is added to a supersaturated solution?
Answer
- The solute precipitates out of the solution.
Explanation:
Solute particles leave the solution and form a crystalline precipitate when a solute crystal is added to a supersaturated solution. Seeding refers to the addition of the solute crystal.
View full question & answer→Question 471 Mark
Answer
- Solute and solvent
Explanation:
The solution is made up of two components that is solute and solvent.
View full question & answer→Question 481 Mark
Which has the lowest boiling point at 1atm pressure?
Question 491 Mark
If 2gm of NaOH is present is 200ml of its solution, its molarity will be:
Question 501 Mark
A liquid is kept in a closed vessel. If a glass plate (negligible mass) with a small hole is kept on top of the liquid surface, then the vapour pressure of the liquid in the vessel is :
Answer
- Same as what would be if the glass plate were removed
Explanation:
The vapour pressure of the liquid in the vessel is same as what would be if the glass plate were removed. Vapour pressure is characteristic property of a solvent at a temperature.
View full question & answer→Question 511 Mark
$H_2S$ is a toxic gas used in qualitative analysis. If solubility of $H_2S$ in water at $\text{STP}$ is $0.195m.$ what is the value of $K_H$?
View full question & answer→Question 521 Mark
In comparison to a $0.01M$ solution of glucose, the depression in freezing point of a $0.01\ \ce {M MgCl_2}$ solution is $........$
AnswerDepression in freezing point is a colligative property. In case of $\ce{MgCl_2}$ value of van’t.
Hoff factor will be more. No. of ions yielded when a molecule of $\ce{MgCl_2}$ gets dissociated in its aqueous solution is $= 3.$
Thus one molecule of $0.01\ \ce{M MgCl_2}$ gives out three particles$/ $ ions in solution.
there by increasing the number of particles present in its solution to three times.
It is because of this that depression in freezing point of $0.01\ \ce{M MgCl_2}$ will be three times as compared to that of $0.01M -$ glucose solution.
where no dissociation of the molecule takes place.
View full question & answer→Question 531 Mark
The Van't Hoff factors i for an electrolyte which undergoes dissociation and association in solvents are respectively:
Answer
- Greater than one and less than one
Explanation:
In case of association of solute particles in solution, the observed molecular weight of solute being more than the normal, the value of factor 'i' is less than unity (i.e. i < 1), while for dissociation the value of i is greater than unity (i.e. i > 1), because the observed molecular weight has lesser value than normal molecular weight.
View full question & answer→Question 541 Mark
The relative lowering in vapour pressure is proportional to the ratio of number of :
Answer
- Solute molecules to the total number of molecules to the total number of molecules in solution.
Explanation:
Relative lowering of vapour pressure. The vapour pressure of a liquid is the pressure of the vapor which is in equilibrium with that liquid. The vapour pressure of a solvent is lowered when a non-volatile solute is dissolved in it to form a solution.
View full question & answer→Question 551 Mark
Vapour pressure of a pure liquid X is 2atm at 300K. It is lowered to atm on dissolving 1 gof Y in 20g of liquid X. If molar mass of X is 200, what is the molar mass of Y?
Question 561 Mark
Which of the following is a true solution?
Question 571 Mark
A solution containing 10.2g glycerine per litre is isotonic with a 2% solution of glucose. What is the molecular mass of glycerine?
Question 581 Mark
Which of the following solutions does not show positive deviation?
Answer
- Toluene and Benzene
Explanation:
Toluene and Benzene are very similar molecules and hence are ideal solution, others are solutions showing positive deviation (Theory based. To be memorized.)
View full question & answer→Question 591 Mark
Which of the following factor (s) affect the solubility of a gaseous solute in the fixed volume of liquid solvent?
(a) Nature of solute (b) Temperature (c) Pressure
Answer
- (a) and (c) at constant T.
- (a) and (b) at constant P.
Explanation:
At constant temperature, the solubility of a gaseous solute in liquid depends on nature of solute and pressure. At constant pressure, solubility is dependent upon nature of solute and temperature.
View full question & answer→Question 601 Mark
A closed vessel is maintained at a constant temperature. It is first evacuated and then vapour is injected into it continuously. The pressure of the vapour in the vessel is:
Answer
- First increases and then remains constant
Explanation:
The molecules of a gas are in a state of random motion. They continuously collide against the walls of the container. Even at ordinary temperature and pressure, the number of molecular collisions with walls is very large. During each collision, certain momentum is transferred to the walls of the container. The pressure exerted by the gas is due to continuous bombardment of gas molecules against the walls of the container. Due to this continuous bombardment, the walls of the container experience a continuous force which is equal to the total momentum imparted to the walls per second. The average force experienced per unit area of the walls of the container determines the pressure exerted by the gas. This should be clear from the fact that although the molecule collisions are random, the pressure remains constant.
View full question & answer→Question 611 Mark
Which of the following binary mixtures will have same composition in liquid and vapour phase?
Answer
- Water-Nitric acid.
- Water-Ethanol.
Explanation:
Non-ideal solution mixtures with same composition in liquid and vapour phase are azeotropes. Water-nitric acid has maximum boiling azeotrope and water-ethanol has a minimum boiling azeotrope.
View full question & answer→Question 621 Mark
A drop each of two non$-$corrosive and nonirritating liquids $A$ and $B$ at a temperature of $22^{\circ}C$ are placed on the skin. Liquid $A$ gives a more cooling sensation than liquid $B.$ Which of the following can be said about the liquids $A$ and $B$?
AnswerLiquid $A$ gives cooling sensation means liquid $A$ is absorbing more heat from the skin, so, liquid $A$ and $B$ can be differentiated as liquid $A$ has lower latent heat of vaporisation than that of liquid $B.$
View full question & answer→Question 631 Mark
The Van't Hoff factor of $\ce{0.1M Ba(NO_3)_2}$ solutions is $2.74.$ The degree of dissociation will be:
View full question & answer→Question 641 Mark
For which solution the value of Van't hoff factor is not equal to 1?
Answer
- Acetic acid
Explanation:
Glucose, sugar and fructose are non- electrolytes, acetic acid is weak elecrolyte and hence dissociates in hydrogen and acetate ions.
Colligative property depends on number of particles present in the solution.
van't Hoff factor is ratio of observed colligative property to theoretical colligative property.
Therefore, van't Hoff factor of acetic acid is greater than 1.
View full question & answer→Question 651 Mark
How much oxygen is dissolved in $100\ mL$ water at $298K$ if partial pressure of oxygen is $0.5\ \text{atm}$ and $K = 1.4 \times 10^{-3} \text{mol/ L/ atm}$?
View full question & answer→Question 661 Mark
Identify which of the following statements is FALSE.
Answer
- During a phase transition, the temperature of a substance must be constant.
Explanation:
During phase transition, temperature is taken on the x-axis of the phase transition curve, hence, during phase transition the temperature of substance changes.
View full question & answer→Question 671 Mark
At a certain temperature, the vapour pressure of water is 50mm. The relative lowering of vapour pressure of a solution containing 36g of glucose in 900g of water is:
Question 681 Mark
Relative lowering of vapour pressure is a colligative property because__________.
Answer
- It depends on the concentration of a non electrolyte solute in solution and does not depend on the nature of the solute molecules.
- It depends on number of particles of electrolyte solute in solution and does not depend on the nature of the solute particles.
Explanation:
Relative lowering of vapour pressure depends on concentration of non-electrolyte solute in solution and number of particles of electrolyte solute. It does not depend on nature of solute in both conditions.
View full question & answer→Question 691 Mark
Mole fraction of glycerine $\ce{C_3H_5(OH)_3}$ in solution containing $36g$ of water and $46g$ of glycerine is:
View full question & answer→Question 701 Mark
If two liquids A and B form minimum boiling azeotrope at some specific composition then ____________.
Answer
- A–B interactions are weaker than those between A–A or B–B.
Explanation:
- The solutions which show large positive deviation from Rault's law form minimum boiling azeotrope at some specific composition.
- In case of positive deviation from Rault's law A-B interactions are weaker than those between A–A or B–B.
View full question & answer→Question 711 Mark
An ideal binary solution is prepared by two liquids A and B, with $\text{P}^\circ_\text{A}>\text{P}^\circ_\text{B}.$Then:
Answer
- A - B interactions are similar to A - A and B - B interactions.
Explanation:
For an ideal binary solution containing two liquids A and B, A - B interactions are similar to A - A and B - B interactions.
View full question & answer→Question 721 Mark
Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?
Answer
- Methanol and acetone.
Explanation:
Mixture of Methanol and acetone shows positive deviation because methanol-methanol and acetone-acetone interactions are more than methanol-acetone. The more number of hydrogen bonds are broken the less number of new H-bonds are formed.
View full question & answer→Question 731 Mark
We have three aqueous solutions of $\ce{NaCl}$ labelled as $'A\ ’, 'B\ ’$ and $'C\ ’$ with concentrations $0.1M, 0.01M$ and $0.001M,$ respectively. The value of van’t Hoff factor for these solutions will be in the order $....$
AnswerThe value of van’t Hoff’s factor will be $i_A= i_{B }= i_C$ due to complete dissociation of strong electrolyte $\ce{(NaCl)}$ in dilute solutions. On complete dissociation value of i for $\ce{(NaCl)}$ is $2.$
View full question & answer→Question 741 Mark
100 mL of liquid A and 25 mL of liquid B are mixed to formal solution of volume 125 mL. Then the solution is___________.
Answer
- ideal
Explanation:
As change in volume $(\triangle\text{V})$ is zero so the solution is ideal. View full question & answer→Question 751 Mark
Equipment needed for measuring the vapour pressure of a liquid:
Answer
- Manometer
Explanation:
A Manometer is a device to measure pressures. A common simple manometer consists of a U shaped tube of glass filled with some liquid. Typically the liquid is mercury because of its high density.
View full question & answer→Question 761 Mark
Answer
- Sum of the numbers of electrons and protons of an atom.
View full question & answer→Question 771 Mark
For carrying reverse osmosis for desalination of water the material used for making semipermeable membrane is:
Question 781 Mark
$K_H$ value for $\ce{Ar(g), CO_2(g), HCHO(g)}$ and $CH_4(g)$ are $40.39, 1.67, 1.83 \times 10^{-5}$ and $0.413$ respectively. Arrange these gases in the order of their increasing solubility.
Answer$\ce{Ar < CO_{2 }< CH_{4 }< HCHO}$ Explanation: Higher the value of $K_H$ lower will be the solubility of the gas at a given pressure,
hence the solubility of given gases would increase with increase in $K_H$ values.
View full question & answer→Question 791 Mark
The van't Hoff factor for a solute which does not dissociate or associate in solution is:
Answer
- 1
Explanation:
The Van't Hoff factor for a solute which does not dissociate or associate in solution is 1 as it is non-electrolyte.
View full question & answer→Question 801 Mark
The vapour pressures of two liquids A and B in their pure states are in the ratio of 1 : 2. A binary solution of A and B contains A and B in the mole proportion of 1 : 2. The mole fraction of A in the vapour phase of the solution will be:
Answer
- 0.2
Explanation:
$\frac{\text{P}^\circ_\text{A}}{\text{P}^\circ_\text{B}}=\frac{1}{2}$
$\frac{\text{X}_{\text{A}}}{\text{X}_{\text{B}}}=\frac{1}{2}$
$\text{P}_{\text{T}}\gamma_\text{A}=\text{P}^\circ_\text{A}\text{x}_\text{A}$
$\therefore\frac{\gamma_\text{A}}{\gamma_\text{B}}=\frac{\text{P}^\circ_\text{A}}{\text{P}^\circ_\text{B}}\frac{\text{X}_\text{A}}{\text{X}_\text{B}}$
We know $\gamma_\text{A}+\gamma_{\text{B}}=1$
$\therefore\gamma_\text{A}=0.2$ View full question & answer→Question 811 Mark
At same temperature which pair of the following solutions are isotonic?
AnswerIsotonic solutions have the same osmotic pressure and same molar concentration.
The solution of $0.1M Ba(NO_3)_2$ and $0.1M Na_2SO_4$ are isotonic.
The osmotic pressure of $0.1M Ba(NO_{3})_2$
$= iMRT = 3 \times 0.1RT = 0.3RT$
Osmotic pressure of $0.1M Na_2SO_{4}$
$= iMRT = 3 \times 0.1RT = 0.3RT$
The correct answer is "The solution of $0.1M Ba(NO_3)_2$ and $0.1M Na_2SO_4$ are isotonic".
View full question & answer→Question 821 Mark
Which of the following conditions is not correct for ideal solution:
Answer
- Lonisation of solute should occurs to a small extent
Explanation:
In an ideal solution, no change in volume on mixing, no change in enthalpy on mixing and it obeys Raoults law but ionisation of solute should not occur to a small extent.
View full question & answer→Question 831 Mark
What is the molality of an aqueous solution,whose relative lowering of vapour pressure is 0.1
Question 841 Mark
Which one of the following electrolytes has the same value of van't Hoff's factor $(i)$ as that of $\ce{Al_2(SO_4)_{3 }}($if all are $100\%$ ionised$)$?
AnswerVan't Hoff factor $i = \frac{\text{number of solute particles present in solution}}{\text{theoretical number of solute particles due to solution of non electrolyte }}$
$=\frac{\text{n(observed)}}{\text{n(theoretical)}}.$
$1$ molecule of $\ce{Al_2(SO_4)_3}$ ionizes in solution to produce $5$ ions.
$\text{Al}_2(\text{SO}_4)_3\rightarrow2\text{Al}^{3+}+3\text{SO}^2_4$
Hence, $i =\frac{\text{n(observed)}}{\text{n(theoretical)}}=\frac{5}{1}=5.$
$1$ molecule of $\ce{K_4[Fe(CN)_{6}]}$ ionize in solution to produce $5$ ions.
$\ce{K_4[Fe(CN)_6] \rightarrow 4K^+ +[Fe(CN)_6]^{4−}}$
Hence, $i =\frac{\text{n(observed)}}{\text{n(theoretical)}}=\frac{5}{1}=5.$
Thus, $\ce{K_4[Fe(CN)_{6}]}$ has the same value of van't Hoff's factor
$(i)$ as that of $\ce{Al_2(SO_4)_3 }($assuming $100\%$ ionization$).$
Note: $1$ molecule each of $\ce{Al(NO_3)_3, K_2SO_{4}}$ and $\ce{K_3[Fe(CN)_6]}$
ionizes in solution to produce $4, 3$ and $4$ ions respectively.
View full question & answer→Question 851 Mark
A student slowly mixes salt into 25ml of water until no more salt dissolves in it. The student could make more salt dissolve in the solution by:
Answer
- Heating it
Explanation:
As no more salt is dissolving in the solution, the solution has became saturated solution. The student can dissolve more solution by heating the solution as on heating the saturated solution become supersaturated. After, the solution become supersaturated, no more salt can be dissolved, it will precipitate out.
View full question & answer→Question 861 Mark
The value of observed and calculated molecular weight of silver nitrate are 92.64 and 170 respectively. The degree of dissociation of silver nitrate is:
Question 871 Mark
When heating of a miscible solution begins, vapours formed will be:
Answer
- Of both liquids with a higher concentration of liquid having low boiling point
Explanation:
When heating begins in miscible solutions, vapours will be of both liquids with a higher concentration of liquid having a low boiling point (since that component will be more volatile in nature).
View full question & answer→Question 881 Mark
Which of the following solutions will have the highest boiling point$:$
Answer$\ce{FeCl_3}$ solution $(\text{T}_\text{b}=\text{T}_\text{b}^0+\Delta\text{T}_\text{b})$
As number of ions produced is maximum in $\ce{FeCl_3}$ solution.
The colligative property $\Delta\text{T}_\text{b}$ will be maximum in case of $\ce{FeCl_3}.$
View full question & answer→Question 891 Mark
When two perfect solutions with volume V each are combined, What is the volume of the solution as a result?
Answer
- 2V
Explanation:
When two perfect solutions are mixed, there is no change in volume.
View full question & answer→Question 901 Mark
Relative lowering of vapour pressure of a solution is equal to:
Answer
- The mole fraction of solute
Explanation:
Relative lowering of vapour pressure of a solution is equal to the mole fraction of solute. After adding the solute, the vapour pressure of the solution is found to be lower than that of the pure liquid at a given temperature.
View full question & answer→Question 911 Mark
Which of the following would have the lowest vapor pressure in the pure state?
Answer
- Sodium hydroxide because of the strong interparticle forces of ionic solids
Explanation:
Sodium hydroxide have lowest vapour pressure in the pure state because of the strong interparticle forces of ionic solids and also non-volatile in nature.
View full question & answer→Question 921 Mark
At a given temperature, osmotic pressure of a concentrated solution of a substance _____________.
Answer
- Is higher than that at a dilute solution.
Explanation:
$\pi=\text{CRT}$
Where C is concentration of the solution. So, the higher the concentration of solution at given temperature the higher will be the osmotic pressure. View full question & answer→Question 931 Mark
The unit of ebulioscopic constant is $........$
Answer$\text{K}_{\text{b}}=\frac{\Delta\text{T}_{\text{b}}}{\text{m}}=\frac{\text{K}}{\text{mol kg}^{-1}}\text{or K}\text{(molality)}^{-1}$
The unit of ebullioscopic constant is $K \ kg \text{ mol}^{-1}$ or $K$ molality$^{-1}$
View full question & answer→Question 941 Mark
If $\ce{PCl_5}$ is $80\%$ dissociated at $250$ then its vapour density at room temperature will be$:$
View full question & answer→Question 951 Mark
When $20g$ of napthoic acid $\ce{(C_{11}H_8O_2)}$ is dissolved in $50g$ of benzene $(K_f = 1.72\ \ce{K kg/ mol)},$ a freezing point depression of $2K$ is observed. The van't Hoff factor $(i)$ is$:$
View full question & answer→Question 961 Mark
Henry’s law constant for molality of methane is benzene at $298K$ is $4.27 \times 10^5mm \ Hg.$ The mole fraction of methane is nenzene at $298K$ under $760\ mm \ Hg$ is:
Answer$1.78 \times 10^{-3}$
View full question & answer→Question 971 Mark
The pressure at which liquid and vapour can coexist at equilibrium is called the :
Answer
- Saturated vapour pressure
Explanation:
Ordinary evaporation is a surface phenomenon - some molecules have enough kinetic energy to escape. If the container is closed, then an equilibrium is reached where an equal number of molecules return to the surface.
The pressure at which this equilibrium where the coexistence of liquid and vapour is achieved is called the saturated vapor pressure.
View full question & answer→Question 981 Mark
Which of the following have least vapour pressure?
Question 991 Mark
A plant cell shrinks when it is kept in a:
Question 1001 Mark
The mass of a non - volatile non - electrolyte solute (molar mass = 50g mol−1) needed to be dissolved in 114g octane to reduce its vapour pressure to 75% is:
Question 1011 Mark
For a very dilute solution of $\ce{H_3PO_{3}}$ van't Hoff factor is$:$
View full question & answer→Question 1021 Mark
234.2gm of sugar syrup contains 34.2gm of sugar. What is the molal concentration of the solution.
Question 1031 Mark
1M, 2.5 litre NaOH solution is mixed with another 0.5M, 3 litre NaOH solution. Then find out the molarity of resultant solution:
Question 1041 Mark
A solution made up of numerous components in which each component’s property is the weighted sum of its separate properties. The answer is:
Answer
- Ideal Solution
Explanation:
An ideal solution is made up of numerous components, each of which has a property that is the weighted sum of the attributes of the others.
View full question & answer→Question 1051 Mark
$12g$ of a non $-$ volatile solute dissolved in $108g$ of water produces the relative lowering of the vapour pressure of $0.1.$ The molecular mass of the solute is:
Answer$12g$ of a non $-$ volatile solute dissolved in $108g$ of water produces the relative lowering of vapour pressure of $0.1.$The molecular mass of the solute is $20.$
$\frac{\triangle\text{P}}{\text{P}^0}=0.1$
$\frac{\triangle\text{P}}{\text{P}^0}=\frac{\text{W}_2\text{M}_1}{\text{W}_1\text{M}_2}$
$0.1=\frac{12\text{g}\times18\text{g}/\text{mol}}{108\text{g}\times\text{M}_2}$
$\text{M}_2=20\text{g}/\text{ mol}$
Note: $W_{1}$ and $W_2$ are weights of water and solute respectively.
$M_{1}$ and $M_{2}$ are molecular weights of water and solute respectively.
View full question & answer→Question 1061 Mark
The value of Henry’s constant $K_H$ is $........$
AnswerThe value of Henry's constant $K_H$ is greater for gases with lower solubility because of the mathematical relation.
$\text{P}=\text{K}_\text{H}\times\text{x}$
$\text{K}_\text{H}=\frac{\text{P}}{\text{x}}$
where, $K_H$ represents Henry's constant, $p$ is partial pressure of the gas in vapour phase, and $x$ denotes mole fraction of the gas in solution.
Thus $K_H$ is inversely proportional to mole fraction of gas in solution $($representing its solubility$).$
View full question & answer→Question 1071 Mark
Which of the following aqueous solutions should have the highest boiling point?
AnswerIn $1.0\ce{M Na_2SO_4}$ solution vant $H$ off factor, $i > 1$ and is maximum when compared with the other three given electrolytes.
So, the extent of dissociation in case of $1.0\ce{M Na_2SO_4}$ would be highest yielding maximum no. of ions as compared to the other given electrolytes in their $1.0M$ solutions.
View full question & answer→Question 1081 Mark
Which one of the following is the ratio of the lowering of vapour pressure of $0.1M$ aqueous solutions of $BaCl_2, NaCl$ and $Al_2(SO_4)_3$ respectively?
AnswerLowering of vapour pressure is a colligative property. It depends on the number of particles of the solute.$\text{BaCl}_2\rightleftharpoons\text{Ba}^{2+}+2\text{Cl}^−; 3\text{ions}$
$\text{NaCl}\rightleftharpoons\text{Na}^++\text{Cl}^−; 2\text{ions}$
$\text{Al}_2(\text{SO}_4)_3\rightleftharpoons2\text{Al}^{3+}+3\text{SO}^{3-}_4; 5\text{ ions}$
Hence, the ratio of lowering of vapour pressure is $3 : 2 : 5$ since the concentration of the solutions are same.
View full question & answer→Question 1091 Mark
50L of a certain liquid is confined in a piston system at the external pressure 100 atm. This pressure is suddenly released and liquid is expanded against the constant one atmosphere pressure, volume of the liquid increases by 1L and the final pressure on the liquid is 10atm. Find the magnitude of work done.
Question 1101 Mark
When a solute is present in trace quantities the following expression is used:
Question 1111 Mark
The heat of solution or mixing has a negative side.
Answer
- Heat of dissolution
Explanation:
The heat of solution or mixing has a negative side. Dissolution’s heat.
View full question & answer→Question 1121 Mark
Which characteristics the weak inter molecular forces of attraction in a liquid?
Answer
- High vapour pressure
Explanation:
The stronger the intermolecular forces between the molecules, the harder it is for vaporization to occur since more energy is required to break the bonds holding the molecules together. So, weak intermolecular forces means high vapour pressure.
View full question & answer→Question 1131 Mark
What weight of glycerol should be added to 600g of water in order to lower its freezing point by 10°C?
Question 1141 Mark
For an ideal liquid solution, which of the following is unity?
Answer
- Activity coefficient
Explanation:
An activity coefficient is a factor used in thermodynamics to account for deviations from ideal behavior in a mixture of chemical substances.
Hence, for an ideal liquid solution, that deviation is 0, as the mole fraction of other substance is 0.
View full question & answer→Question 1151 Mark
The vapour pressure of the solution containing $30g$. of non - volatile solute of molecular weight $60$ in $360gm$ of water approximately at $30^0c$ is: $($vapour pressure of water at $30^0c = 24\ mm of \ Hg)$
AnswerGiven,
mass of solute $30g$
mass of solvent $360g$
the molecular mass of solute $60g$
the molecular mass of solvent that is water is $18g$
The pressure of pure water is $24\ mm\ Hg$
$\frac{\text{p}_0-\text{p}}{\text{P}}$ = moles of solute/ total no.of moles
$\frac{\text{p}_0-\text{p}}{\text{P}}=\frac{\frac{30}{60}}{\frac{30}{60}+\frac{360}{180}}$
$\frac{\text{p}_0-\text{p}}{\text{P}}=\frac{1}{41}$
$\text{P}=23.4\text{mmHg}$
View full question & answer→Question 1161 Mark
The possible van't Hoff factor for sodium chloride in water assuming sodium chloride is partially ionized:
Question 1171 Mark
Which of the following options is not a viable option?
Answer
- Aerated drinks
Explanation:
A solid solution is a one - or more - solute solid - state solution in a solvent. Solid solutions include brass, bronze, and hydrated salts. Liquid solutions include aerated beverages.
View full question & answer→Question 1181 Mark
The values of Van’t Hoff factors for $\ce{KCl, NaCl}$ and $\ce{K_2SO_4},$ respectively, are $........$
Answer$\ce{KCl (K^+ + Cl)}$ and $\ce{NaCl(Na^+ + Cl)}$ ionize to give $2$ ions and $\ce{K_2SO_4(2K^+ + SO^-_4)}$ ionizes to give $3$ ions.
thus, van’t Hoff factors for $\ce{KCl, NaCl}$ and $\ce{K_2SO_{4 }}$ are $2, 2$ and $3$ respectively.
View full question & answer→Question 1191 Mark
3 moles of P and 2 moles of Q are mixed, what will be their total vapour pressure in the solution if their partial vapour pressures are 80 and 60 torr respectively?
Question 1201 Mark
A zinc metal sample containing zinc chloride as impurity was made to react with an excess of dilute hydrochloric acid at $27^\circ\ C$. Liberated hydrogen gas is collected at $760\ mm\ Hg$ pressure that occupies $780.0\ cm^3$ volume. If the vapour pressure of water at $27^\circ\ C$ is $14\ mm\ Hg,$ what is the volume of $H_2$ at $\text{STP}$? The Standard pressure is $760\ mm\ Hg ($molar volume of gas at standard temperature and pressure, $\text{STP} = 22.4\ dm^3)$
View full question & answer→Question 1211 Mark
At equilibrium the rate of dissociation of a solid solute in a volatile liquid solvent is:
Answer
- Equal to the rate of crystallisation
View full question & answer→Question 1221 Mark
A beaker contains a solution of substance ‘A’. Precipitation of substance ‘A’ takes place when small amount of ‘A’ is added to the solution. The solution is _________.
Answer
- Supersaturated.
Explanation:
When small amount of solute is added to its solution and it does not dissolve and get precipitated then this solution is supersaturated solution.
View full question & answer→Question 1231 Mark
Molarity of liquid HCl will be, if density of solution is 1.17 gm/cc.
Question 1241 Mark
Which substance would dissolve fastest in water?
Answer
- 1g granulated sugar
Explanation:
Each Granulated sugar is touched with water so exposed surface is highest from others so its solubility is highest.
View full question & answer→Question 1251 Mark
Which of the following solutions shows positive deviation from Raoult’s law?
Question 1261 Mark
Colligative properties depend on __________.
Answer
- The number of solute particles in solution.
Explanation:
Colligative properties depend upon the number of solute particles in the solution and independent of its nature.
View full question & answer→Question 1271 Mark
Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon _______.
Answer
- Pressure.
Explanation:
Solubility of a solid in liquid does not depend upon pressure since solid and liquids are almost incompressible.
View full question & answer→Question 1281 Mark
Which characteristic the weak intermolecular forces of attraction in a liquid?
Answer
- High vapour pressure
Explanation:
High vapour pressure leads to the weak intermolecular forces of attraction in a liquid.Weaker are the intermolecular forces of attractions, more is the tendency for evaporation, more is vapour pressure, lower is boiling point.
View full question & answer→Question 1291 Mark
Calculate the vapour pressure of aqueous 0.1m glucose solution at 300K temperature, the vapour pressure of water is 0.03bar at 300K temperature.
Question 1301 Mark
Two containers, X and Y at 300K and 350K with water vapour pressures 22mm and 40mm respectively a are connected, initially closed with a valve. If the valves opened.
Answer
- The final pressure in each container is 31mm.
View full question & answer→Question 1311 Mark
The Vant Hoff factor for a dilute solution $\ce{K_3[Fe(CN)_6]}.$
View full question & answer→Question 1321 Mark
_____________ obeys Raoult’s law in all stages of concentration.
Answer
- Ideal Solution
Explanation:
At all concentration levels, Ideal Solution follows Raoult’s law.
View full question & answer→Question 1331 Mark
The volume occupied by a single gas in a mixture at the same temperature and pressure is referred to as the single - gas volume.
Answer
- Partial volume
Explanation:
At the same temperature and pressure, the volume occupied by a single gas alone in a combination is a portion of a volume.
View full question & answer→Question 1341 Mark
Which of the following are true solutions?
AnswerThe definition of true solution is a homogeneous mixture of two or more substances in which substance dissolved $($solute$)$ in solvent has the size of the particle less than $10^{−9}m$ or $1\ nm.$ So the perfect example of true solution is $\text{ENO}$ salt in water. $\text{ENO}$ is perfectly soluble in water and has minimum size.
View full question & answer→Question 1351 Mark
A mixture of benzene and toluene forms:
Answer
- An ideal solution
Explanation:
Mixing of benzene and toluene does not involve any kind of decrease or increase in interaction forces in between molecules so they form ideal solution.
View full question & answer→Question 1361 Mark
Most of the processes in our body occur in:
Question 1371 Mark
The vapour pressure of water at 300K in a closed container is 0.4 atm. If the volume of the container is doubled, its vapour pressure at 300K will be:
Answer
- 0.4 atm
Explanation:
Vapour pressure will be the same because it doesn't depend on the volume it depends only on Temperature.
View full question & answer→Question 1381 Mark
When a solution is diluted at constant temperature, its vapour pressure:
Answer
- Increases
Explanation:
When a solution is diluted at a constant temperature, its vapour pressure increases.
When the solution is diluted, the mole fraction of solute decreases and the mole fraction of solvent increases.
Hence, the relative lowering in vapour pressure decreases and the vapor pressure increases.
View full question & answer→Question 1391 Mark
On the basis of information given below mark the correct option.
Information:
- In bromoethane and chloroethane mixture intermolecular interactions of A–A and B–B type are nearly same as A–B type interactions.
- In ethanol and acetone mixture A–A or B–B type intermolecular interactions are stronger than A–B type interactions.
- In chloroform and acetone mixture A–A or B–B type intermolecular interactions are weaker than A–B type interactions.
Answer
- Solution (A) will follow Raoult’s law.
Explanation:
For an ideal solution A-A and B-Bintermolecular interactions should be nearly same as A-B type interactions.
View full question & answer→Question 1401 Mark
Which of the following property indicates weak intermolecular forces of attraction in liquid?
Answer
- High vapour pressure
Explanation:
The molecules that are having weak intermolecular forces of attraction, they can easily dissociate and convert into vapour state, so, molecules with weak intractions have high vapour pressure.
View full question & answer→Question 1411 Mark
What will be the degree of dissociation of $\ce{0.1M Mg(NO_3)_2}$ solution if van’t Hoff factor is $2.74$?
View full question & answer→Question 1421 Mark
At equilibrium the rate of dissolution of a solid solute in a volatile liquid solvent is __________.
Answer
- Equal to the rate of crystallisation.
Explanation:
This happens as per conditions attained at equilibrium state; i.e. rate of forward reaction (dissolution) = rate of backward reaction (crystallisation)
View full question & answer→Question 1431 Mark
The system that forms maximum boilingazetrope is:
Question 1441 Mark
The law which indicates the relation’-hip between solubility of a gas in liquid and pressure rs:
Question 1451 Mark
To an aqueous solution of $\ce{NaI},$ increasing amounts of solid $\ce{HgI_{2}}$ is added, the vapour pressure of the solution:
AnswerIncreases to a constant value.
View full question & answer→Question 1461 Mark
Which of the following plot does not represent the behaviour of an ideal binary liquid solution of $A$ and $B$?
AnswerPlot of $p_{total}$ vs $x_{B}$ is parabola
View full question & answer→Question 1471 Mark
Vant Hoff factor for a dilute solution of glucose is:
Answer
- 1
Explanation:
Solution of glucose is a non-electrolytic solution.
For a non - electrolytic solution, vant hoff factor is 1.
View full question & answer→Question 1481 Mark
In an endothermic process, solubility increases with ______ in temperature:
Answer
- Increase
Explanation:
The effect of temperature on solubility depends on the type of reaction that occurs during the process of dissolving the solute in the solvent. In endothermic reactions, increasing the temperature increases the solubility of the solute in a solution. In exothermic reactions, increasing the temperature decreases the solubility of the solute.
View full question & answer→Question 1491 Mark
Partial pressure of a solution component is directly proportional to its mole fraction. This is known as:
Question 1501 Mark
For a binary ideal liquid solution, the variation in total vapour pressure versus composition of solution is given by which of the curves?
Answer
-
-
Explanation:
The slopes at (i) and (iv) are straight lines, therefore they represent ideal behaviour of the solution.
View full question & answer→MCQ 1511 Mark
Molarity of pure water is -