MCQ 511 Mark
If the bond energies of $\ce{H-H, Br-Br}$ and $\ce{H-Br}$ are $433, 192$ and $364 \text{ kJ mol}^{-1}$, respectively, then $\Delta\text{H}^\circ$ for the reaction. $\ce{H_2(g) + Br(g) \rightarrow 2HBr(g)}$ is :
- A
$-\ 261kJ$
- ✓
$-\ 103kJ$
- C
$+\ 261kJ$
- D
$-\ 1031kJ$
AnswerCorrect option: B. $-\ 103kJ$
$\Delta\text{H}=\text{B}_{\text{H}-\text{H}}+\text{B}_{\text{Br}-\text{Br}}-2\text{B}_{\text{H}-\text{Br}}$
$=433+192-2\times364$
$=625-728$
$=-103\text{kJ}$
View full question & answer→MCQ 521 Mark
The temperature at the bottom of a high water fall is higher than that at the top because :
- A
by itself heat flows from higher to lower temperature
- B
the difference in height causes a difference in pressure
- C
thermal energy is transformed into mechanical energy
- ✓
mechanical energy is transformed into thermal energy
AnswerCorrect option: D. mechanical energy is transformed into thermal energy
The water at the top of the waterfall, falls and gains velocity.
The potential energy it has converts into kinetic energy.
When the water lands at the bottom, the kinetic energy converts into heat and hence the water is warmer at the bottom.
View full question & answer→MCQ 531 Mark
Which heat is produced throughout the conducting wire?
AnswerAs the heat produced in the conductor by following Joule's law of heating or cooling. $Sp,$ the produced heat is Joule heat.
View full question & answer→MCQ 541 Mark
Hess law of heat summation includes :
- A
- ✓
Initial reactants and final products
- C
- D
AnswerCorrect option: B. Initial reactants and final products
Hess law includes initial reactants and final products.
View full question & answer→MCQ 551 Mark
Which of the following is an endothermic process?
- A
$2\text{H}_2+\text{O}_2\rightarrow2\text{H}_2\text{O};\ \Delta\text{H}=-\text{q}\text{ kJ}$
- ✓
$\text{N}_2+\text{O}_2\rightarrow2\text{NO}-\text{Y kJ}$
- C
$\text{CH}_4+2\text{O}_2\rightarrow\text{CO}_2+2\text{H}_2\text{O};$
$\Delta\text{H}=-\text{X kJ mol}^{-1}$
- D
$\text{NaOH}+\text{HCl}\rightarrow\text{NaCl}+\text{H}_2\text{O}+\text{Z kJ}$
AnswerCorrect option: B. $\text{N}_2+\text{O}_2\rightarrow2\text{NO}-\text{Y kJ}$
It is an endothermic process as heat is being absorbed.
View full question & answer→MCQ 561 Mark
The enthalpies of all elements in their standard states are :
- A
- ✓
- C
$< 0.$
- D
Different for each element.
AnswerThe enthalpies of all elements in their standard states are zero.
View full question & answer→MCQ 571 Mark
$\Delta\text{S}(\text{A}\rightarrow\text{C})=50\text{ev},$$\Delta\text{S}(\text{C}\rightarrow\text{D})=30\text{ev},$
$\Delta\text{S}(\text{B}\rightarrow\text{D})=20\text{ev}$
$\text{A}\rightarrow\text{B}$
$\downarrow\ \ \ \ \ \uparrow$
$\text{C}\rightarrow\text{D}$
The entropy change for $A \rightarrow B$ would be :
- A
$100ev$
- ✓
$60ev$
- C
$-\ 60ev$
- D
$-\ 100ev$
AnswerCorrect option: B. $60ev$
$\Delta\text{S}(\text{A}\rightarrow\text{B})=\Delta\text{S}(\text{A}\rightarrow\text{C})$
$+\Delta\text{S}(\text{C}\rightarrow\text{D})+\Delta\text{S}(\text{D}\rightarrow\text{B})$
$=50+30-\Delta\text{S}(\text{D}\rightarrow\text{B})$
$=50+30-20=60\text{ev}$
View full question & answer→MCQ 581 Mark
AnswerCombustion is an oxidation reaction and during this reaction, heat is produced.
In this type of reaction, bonds are broken first and then new bonds may be created results in new material formation.
So, it is always an exothermic reaction.
View full question & answer→MCQ 591 Mark
Which of the following statements is correct?
- A
The presence of reacting species in a covered beaker is an example of open system.
- B
There is an exchange of energy as well as matter between the system and the surroundings in a closed system.
- ✓
The presence of reactants in a closed vessel made up of copper is an example of a closed system.
- D
The presence of reactants in a thermos flask or any other closed insulated vessel is an example of a closed system.
AnswerCorrect option: C. The presence of reactants in a closed vessel made up of copper is an example of a closed system.
If a closed reaction vessel is made of copper, it will work as closed system because in such system heat will be exchanged with the surroundings but no matter will exchange.
View full question & answer→MCQ 601 Mark
A bomb calorimeter is used to measure the value of heat of reaction at a constant :
AnswerFor combustion reactions, we often enclose all reactants in an explosive-proof steel container, called the bomb whose volume does not change during a reaction. The bomb is then submerged in water or other liquid that absorbs the heat of reaction. The heat capacitor of the bomb plus other things is then measured using the same technique as other calorimeters. Such an instrument is called a bomb calorimeter, and its application is called the bomb calorimetry. For combustion reactions, we often enclose all reactants in an explosive $-$ proof steel container, called the bomb whose volume does not change during a reaction. The bomb is then submerged in water or other liquid that absorbs the heat of reaction.
View full question & answer→MCQ 611 Mark
The resultant heat change in a reaction is the same whether it takes place in one or several stages. This statement is called:
AnswerThe enthalpy change for the overall process is the sum of the enthalpy change of the steps in the process.
View full question & answer→MCQ 621 Mark
The statement "The change of enthalpy of a chemical reaction is same whether the reaction takes place in one or several steps" is :
- A
- B
- C
first law of thermodynamics
- ✓
AnswerThe statement "The change of enthalpy of a chemical reaction is same whether the reaction takes place in one or several steps" is Hess’s law of constant heat summation.
View full question & answer→MCQ 631 Mark
Specific heat may be defined as :
AnswerCorrect option: D. Heat capacity $g^{-1}$
The amount of heat required to raise the temperature of a unit mass of a substance by one $-$ degree celsius is known as specific heat. Heat capacity is the amount of heat added to a substance to raise its temperature by one kelvin.
Thus, specific heat may be defined as heat capacity per gram.
View full question & answer→MCQ 641 Mark
In the given reaction, $\ce{H_2(g) \rightarrow 2H(g)}; \Delta\text{H}=435.0\text{kJ mol}^{-1}$ The enthalpy change is known as :
- A
- ✓
- C
Bond dissociation enthalpy.
- D
Both $(b)$ and $(c).$
Answer$\ce{H_2(g) \rightarrow 2H(g)}; \Delta_\text{a}\text{H}^\circ=435\text{kJ mol}^{-1}$
$H-$ atoms are formed by breaking $H-H$ bond in dihydrogen.
The enthalpy change in this process is known as enthalpy of atomisation $,\Delta_\text{a}\text{H}^\circ.$
View full question & answer→MCQ 651 Mark
A spontaneous reaction occurs:
- A
- B
- C
with outside intervention and slowly
- ✓
by itself but it has now effect on how fast the reaction takes
AnswerCorrect option: D. by itself but it has now effect on how fast the reaction takes
Explanation: (D) by itself but it has now effect on how fast the reaction takes
A spontaneous reaction occurs by itself but it has no effect on how fast the reaction takes.
A spontaneous reaction may be very fast but another spontaneous reaction may be very slow.
View full question & answer→MCQ 661 Mark
The state of gas can be described by quoting the relationship between,
- A
Pressure, volume, temperature.
- B
Temperature, amount, pressure.
- C
Amount, volume, temperature.
- ✓
Pressure, volume, temperature, amount.
AnswerCorrect option: D. Pressure, volume, temperature, amount.
State of a system can be described by state functions or state variables which are pressure, volume, temperature and amount of the gas $\text{(PV = nRT)}.$
View full question & answer→MCQ 671 Mark
Two substances $P$ and $Q$ when brought together, form substance $R$ with the evolution of heat. The properties of $R$ are different from both $P$ and $Q$. What is substance $R\ ?$
AnswerSince the substance $R$ is a mixture of two substances, it may either be a mixture or a compound.
In a mixture the constituents retain their properties while in a compound, they lose their properties.
Since the question mentions that $R$ has different property from both $P$ and $Q,$ hence it must be a compound.
View full question & answer→MCQ 681 Mark
Which heat depends on the direction of current?
AnswerIn Peltier effect, heat loss and heat gain depends upon the direction of current.
A typical Peltier heat pump involves multiple junction in series in which direction of current is important.
View full question & answer→MCQ 691 Mark
The enthalpies of elements in their standard states are taken as zero.The enthalpy of formation of a compound.
- A
- B
- ✓
May be positive or negative.
- D
AnswerCorrect option: C. May be positive or negative.
Heat of formation of a compound may be positive or negative, e.g.,
$\text{C}(\text{s})+\text{O}_2(\text{g})\rightarrow\text{CO}_2(\text{g});$
$\Delta\text{H}^\circ=-393.5\text{kJ}\ \text{mol}^{-1}$
$\text{N}_2(\text{g})\frac{1}{2}\text{O}_2(\text{g})\rightarrow\text{N}_2\text{O}(\text{g});$$\Delta\text{H}^\circ=+92\text{kJ}\ \text{mol}^{-1}$
View full question & answer→MCQ 701 Mark
Choose the correct answer. A thermodynamic state function is a quantity :
- A
Used to determine heat changes.
- ✓
Whose value is independent of path.
- C
Used to determine pressure volume work.
- D
Whose value depends on temperature only.
AnswerCorrect option: B. Whose value is independent of path.
View full question & answer→MCQ 711 Mark
Actual flame temperature is always lower than the adiabatic flame temperature, because there is $ .......... :$
- A
no possibility of obtaining complete combustion at high temperature.
- B
always loss of heat from the flame.
- ✓
both $(a)$ and $(b).$
- D
neither $(a)$ nor $(b).$
AnswerCorrect option: C. both $(a)$ and $(b).$
The constant volume adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any work, heat transfer or changes in kinetic or potential energy. The constant pressure adiabatic flame temperature is the temperature that results from a complete combustion process that occurs without any heat transfer or changes in kinetic or potential energy. Its temperature is lower than the constant volume process because some of the energy is utilized to change the volume of the system $($i.e., generate work$).$
View full question & answer→MCQ 721 Mark
What is the free energy change $\triangle G,$ when $1.0$ mole of water at $100^\circ C$ and $1$ atm pressure is converted steam at $100^\circ C$ and $1$ atm pressure : $-$
- A
$+\ 540 \text{ cal}$
- B
$-\ 9800 \text{ cal}$
- C
$+\ 9800 \text{ cal}$
- ✓
$0 \text{ cal}$
AnswerCorrect option: D. $0 \text{ cal}$
As we know that $\triangle G$ at equilibrium is always $0.$
So, here also is equilibrium; so $\triangle G = 0$
View full question & answer→MCQ 731 Mark
Which of the following is not correct?
- A
$\Delta\text{G}$ is zero for a reversible reactio.
- ✓
$\Delta\text{G}$ is positive for a spontaneous reactio.
- C
$\Delta\text{G}$ is negative for a spontaneous reaction.
- D
$\Delta\text{G}$ is positive for a non $-$ spontaneous reaction.
AnswerCorrect option: B. $\Delta\text{G}$ is positive for a spontaneous reactio.
$\Delta\text{G}$ gives a criterion for spontaneity at constant pressure and temperature.
- If $\Delta\text{G}$ is negative $(< 0)$. The process is spontaneous.
- If $\Delta\text{G}$ is positive $(> 0)$. The process is non-spontaneous.
- If $\Delta\text{G}$ is zero then reaction is at equilibrium.
View full question & answer→MCQ 741 Mark
The reverse of a spontaneous reaction is $....... :$
- A
- ✓
- C
- D
There is no way of telling
AnswerThe revere of a spontaneous reaction is always non $-$ spontaneous.
According to the second law of thermodynamics, a reaction is spontaneous if the overall entropy or disorder increases.
If we go back to our cleaning the house analogy, when our home becomes messy, then the entropy increases.
The mess that accumulates is a spontaneous reaction, and as a result, the entropy increases.
View full question & answer→MCQ 751 Mark
For the reaction, $\text{N}_2(\text{g})+3\text{H}_2(\text{g})\rightleftharpoons2\text{NH}_3(\text{g});\ \Delta\text{H}$ is :
- ✓
$\Delta\text{U}-2\text{RT}$
- B
$\Delta\text{U}-\text{RT}$
- C
$\Delta\text{U}+\text{RT}$
- D
$\Delta\text{U}+2\text{RT}$
AnswerCorrect option: A. $\Delta\text{U}-2\text{RT}$
View full question & answer→MCQ 761 Mark
The entropy change can be calculated by using the expression $\Delta\text{S}=\frac{\text{q}_\text{rev}}{\text{T}}\ .$ When water freezes in a glass beaker, choose the correct statement amongst the following :
- A
$\Delta\text{S}_\text{(system)}$ decreases but $\Delta\text{S}_\text{(surrounding)}$ remains the same.
- B
$\Delta\text{S}_\text{(system)}$ increases but $\Delta\text{S}_\text{(surrounding)}$ decreases.
- ✓
$\Delta\text{S}_\text{(system)}$ decreases but $\Delta\text{S}_\text{(surrounding)}$ increases.
- D
$\Delta\text{S}_\text{(system)}$ decreases but $\Delta\text{S}_\text{(surrounding)}$ also decreases.
AnswerCorrect option: C. $\Delta\text{S}_\text{(system)}$ decreases but $\Delta\text{S}_\text{(surrounding)}$ increases.
When water freezes, the heat is transferred from system to the surroundings, thus entropy of system decreases but entropy of surroundings increases.
View full question & answer→MCQ 771 Mark
Energy hidden in a definite quantity of substance is :
AnswerInternal energy is the hidden energy in a definite quantity of substance.
View full question & answer→MCQ 781 Mark
Which of the following properties is the measure of the degree of randomness or disorder in the system?
MCQ 791 Mark
The volume of gas is reduced to half from its original volume. The specific heat will be $ .........$
AnswerThe specific heat of a substance is the heat required to raise the temperature of $1$ gram of a substance by one degree $(1K$ or $1^\circ C)$. It is an intensive property and is independent of the volume of the substance.
View full question & answer→MCQ 801 Mark
All natural processes are :
AnswerA spontaneous process is one that occurs on its own, without any energy used from the outside.
For example, a ball will roll down an incline; water will flow downhill; ice will melt into water; radioisotopes will decay; and iron will rust.
So all natural process are spontaneous.
View full question & answer→MCQ 811 Mark
- A
Law of conservation of mass.
- ✓
Law of conservation of energy.
- C
- D
Both $(a)$ and $(b).$
AnswerCorrect option: B. Law of conservation of energy.
Hess's law is based on law of conservation of energy.
View full question & answer→MCQ 821 Mark
On the basis of thermochemical equations $(a), (b)$ and $(c),$ find out which of the algebric relationships given in options $(i)$ to $(iv)$ is correct.
- $\text{C}(\text{graphite})+\text{O}_2(\text{g})\rightarrow\text{CO}_2(\text{g});\Delta_\text{r}\text{H}=\text{x}\text{kJ}\ \text{mol}^{-1}$
- $\text{C}(\text{graphite})+\frac{1}{2}\text{O}_2(\text{g})\rightarrow\text{CO}(\text{g});\Delta_\text{r}\text{H}=\text{y} \text{kJ}\ \text{mol}^{-1}$
- $\text{CO}(\text{g})+\frac{1}{2}\text{O}_2(\text{g})\rightarrow\text{CO}_2(\text{g});\Delta_\text{r}\text{H}=\text{z}\text{kJ}\ \text{mol}^{-1}$
- A
$z = x + y $
- B
$x = y \ – z$
- ✓
$x = y + z$
- D
$y = 2z\ – x$
AnswerCorrect option: C. $x = y + z$
$\text{CO}(\text{g})+\frac{1}{2}\text{O}_2(\text{g})\rightarrow\text{CO}_2(\text{g})$
Adding the reaction $2$ and reaction $3,$ we get $1^\text{st}$ reaction,
$\text{C}+\frac{1}{2}\text{O}_2+\text{CO}+\frac{1}{2}\text{O}_2\rightarrow\text{CO}+\text{CO}_2$
$\text{C}+\text{O}_2\rightarrow\text{CO}_2\ $$\Delta\text{H}=\text{y+z}$
Hence $\text{X = Y + Z}$
View full question & answer→MCQ 831 Mark
For a given reaction, $\Delta\text{H}=35.5\text{kJ mol}^{-1}$ and $\Delta\text{S}=83.6\text{Jk}^{-1}\text{mol}^{-1}.$ The reaction is spontaneous at $($assume that $\Delta\text{H}$ and $\Delta\text{S}$ do not vary with temperature$)$
- A
$T > 425K$
- ✓
- C
$T > 298K$
- D
$T < 425K$
Answer$\Delta\text{G}=\Delta\text{H}-\text{T}\Delta\text{S}$
$=0=35.5\times1000\text{J}-\text{T}\times83.6\text{Jk}^{-1}\text{mol}^{-1}$
$\Rightarrow\text{T}=\frac{35500}{83.6}=425\text{K}$
Above $425K, \Delta\text{G}=-\text{ve},$ therefore process will be spontaneous above $425K.$
View full question & answer→MCQ 841 Mark
Consider the reactions given below. On the basis of these reactions find out which of the algebric relations given in options $(i)$ to $(iv)$ is correct?
- $\text{C}(\text{g})+4\text{H}(\text{g})\rightarrow\text{CH}_4(\text{g});\Delta_\text{r}\text{H}=\text{x}\text{kJ}\ \text{mol}^{-1}$
- $\text{C}(\text{graphite,s})+2\text{H}_2(\text{g})\rightarrow\text{CH}_4(\text{g});\Delta_\text{r}\text{H}=\text{y}\text{kJ}\ \text{mol}^{-1}$
- A
$\text{x}=\text{y}$
- B
$\text{x}=2\text{y}$
- ✓
$\text{x} > \text{y}$
- D
$\text{x} < \text{y}$
AnswerCorrect option: C. $\text{x} > \text{y}$
$x > y$ because same bonds are formed in reactions $(i)$ and $(ii)$ but bonds between reactant molecules are broken only in reaction $(ii)$. As energy is absorbed when bonds are broken, energy released in reaction $(i)$ is greater than that in reaction $(ii).$
View full question & answer→MCQ 851 Mark
Two samples of $\text{DNA, A }$ and $B$ have melting points $340K$ and $350K$ respectively. This is because :
- ✓
$B$ has more $GC$ content than $A$
- B
$A $ has more $GC$ content than $B$
- C
$B$ has more $AT$ cotent than $A$
- D
both have same $AT$ content
AnswerCorrect option: A. $B$ has more $GC$ content than $A$
The $B$ sample of $\text{DNA}$ having higher melting point must be having more $GC$ content as comppared to sample $A$.
Since $GC$ base pair having $3$ hydrogen bonds as compare to $AT$ base pair having only $2$ hydrogen bonds, results in stronger bonding.
View full question & answer→MCQ 861 Mark
For the reaction, $\text{X}_2\text{O}_4(\text{l})\rightleftharpoons2\text{XO}_2(\text{g})$
$\Delta\text{U}=2.1\text{K cal}, \ \Delta\text{S}=20\text{cal K}^{-1}$ at $300K,$ Hence $\Delta\text{G}$ is : $[h = 2 \text{cal}]$
- A
$2.7\text{K cal}$
- ✓
$-2.7\text{K cal}$
- C
$9.3\text{K cal}$
- D
$-9.3\text{K cal}$
AnswerCorrect option: B. $-2.7\text{K cal}$
$\Delta\text{H}=\Delta\text{U}+\Delta\text{n}\text{RT}$
$\Delta\text{H}=2100\text{cal}+2\times2\times300$
$=2100\text{cal}+1200\text{cal}=330\text{cal}$
$\Delta\text{G}=\Delta\text{H}-\text{T}\Delta\text{S}$
$=3300\text{cal}-20\times300$
$=3300\text{cal}-6000\text{cal}$
$=-2700\text{cal}=-2.7\text{K cal}$
View full question & answer→MCQ 871 Mark
AnswerTherm is a non $\text{SI}$ unit of heat energy equal to $\text{ICCF}$ of natural gas and $10000\ B + u$ British thermal units.
View full question & answer→MCQ 881 Mark
Enthalpy of sublimation of a substance is equal to,
AnswerCorrect option: A. Enthalpy of fusion $+$ enthalpy of vapourisatio.
Enthalpy of sublimation of a substance is equal to enthalpy of fusion $+$ enthalpy of vapourisation.
Sublimation is direct conversion of solid to vapour, i.e., solid $\rightarrow $ vapour.
Writing in two steps, we have solid $\rightarrow $ liquid $\rightarrow $ vapour.
Solid $\rightarrow $ liquid requires enthalpy of fusion.
Liquid $\rightarrow $ vapour requires enthalpy of vapourisation.
View full question & answer→MCQ 891 Mark
Which of the following property is not a thermodynamic property of the system?
AnswerA thermodynamic property is that, which is measurable and whose value describes the state of system. Out of the given quantities, heat doesn't describe the state of a system so it is not a thermodynamic property because a system doesn't contain heat but only can transfer heat.
View full question & answer→MCQ 901 Mark
View full question & answer→MCQ 911 Mark
Free energy change for the process $\ce{A(s)\leftrightarrow B(l)}$ will be :
AnswerIn the given process, $A$ and $B$ are in equilibrium, and we know that the free energy change for equilibrium reaction is zero.
View full question & answer→MCQ 921 Mark
- ✓
Heat changes in a chemical reaction.
- B
- C
- D
Influence of pressure on volume of a gas
AnswerCorrect option: A. Heat changes in a chemical reaction.
Hess law deals with the heat changes in a chemical reaction.
View full question & answer→MCQ 931 Mark
Name the apparatus used to measure the heat absorbed or released by a reaction :
AnswerCalorimeter is used to measure the heat absorbed or released by a reaction.
Centrifuge is used to separate precipitate from solution.
Barometer is used to measure pressure.
Balance is used to measure weight of a substance.
Battery is used to provide electricity.
View full question & answer→MCQ 941 Mark
For the reaction $,\mathrm{NaCl}(\mathrm{s}) \rightarrow \mathrm{Na}^{+}(\mathrm{g})+\mathrm{Cl}^{-}(\mathrm{g})$ Identify the enthalpy involved in the above reaction :
- A
- ✓
- C
- D
Enthalpy of dissociation.
AnswerLattice enthalpy of an ionic compound is the enthalpy change which occurs, when one mole of an ionic compound dissociate into its ions in gaseous state.
$\mathrm{NaCl}(\mathrm{s}) \rightarrow \mathrm{Na}^{+}(\mathrm{g})+\mathrm{Cl}^{-}(\mathrm{g})$;
$\Delta_\text{lattice}\text{H}^-=+788\text{ kJ mol}^{-1}$
View full question & answer→MCQ 951 Mark
The enthalpy change when one mole of solute dissolves in a specified amount of solvent is called :
- A
- ✓
- C
- D
Enthalpy of dissociation.
AnswerEnthalpy of solution is the enthalpy change when one mole of solute dissolved in a specified amount of solvent.
View full question & answer→MCQ 961 Mark
Which of the following drives spontaneous reactions?
- ✓
Low enthalpy values and high entropy values.
- B
Low enthalpy values and low entropy values.
- C
High enthalpy values and low entropy values.
- D
High temperatures and low pressures.
AnswerCorrect option: A. Low enthalpy values and high entropy values.
Low enthalpy and high entropy drives spontaneous reactions.
These leads to negative value of Gibbs free energy change.
$\triangle G = \triangle H − T\triangle S$
View full question & answer→MCQ 971 Mark
Which of the following process is non-spontaneous?
- A
Heat flow from hot end to cool end.
- B
Water flow from higher level to lower level.
- ✓
Gas flow from lower pressure region to higher pressure region.
- D
Gas flow from higher pressure region to lower pressure region.
AnswerCorrect option: C. Gas flow from lower pressure region to higher pressure region.
Gas flowing from higher pressure region to lower pressure region is a natural process. Similarly, option $A$ and $B$ are natural.
Natural processes are spontaneous. Therefore, flow of gas from lower pressure to higher pressure region is non $-$ spontaneous.
View full question & answer→MCQ 981 Mark
A reaction, $\text{A + B + C + D + q}$ is found to have a positive entorpy change. The reaction will be :
- A
Possible at high temperature.
- B
Possible only at low temperature.
- C
Not possible at any temperature.
- ✓
Possible at any temperature.
AnswerCorrect option: D. Possible at any temperature.
View full question & answer→MCQ 991 Mark
Regarding a thermochemical equation, wrong statement is :
AnswerCorrect option: D. It tells whether the reaction is possible or not
A thermochemical equation cannot tell whether the reaction is feasible or not. Free energy data is required to determine whether the reaction is feasible or not.
View full question & answer→MCQ 1001 Mark
Whether a reaction is endothermic or exothermic can be indicated by :
AnswerWhether a reaction is endothermic or exothermic can be indicated by enthalpy change.
Enthalpy change is the difference in the enthalpy of products and the enthalpy of reactants.
A positive value of enthalpy change indicates endothermic reaction as the enthalpy of products is more than the enthalpy of reactants.
A negative value of enthalpy change indicates exothermic reaction as the enthalpy of products is less than the enthalpy of reactants.
View full question & answer→