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Chemistry M.C.Q (1 Marks)

The s-block Elements · CBSE STD 11 Science (CBSE - English Medium). 191 questions.

Questions · Page 2 of 4

M.C.Q (1 Marks)

MCQ 511 Mark
Sodium hydroxide is prepared by the electrolysis of sodium chloride solution, the electrodes used as cathode and anode are respectively:
  • A
    Mercury and platinum.
  • B
    Platinum and mercury.
  • ✓
    Mercury and carbon.
  • D
    Carbon and mercury.
Answer
Correct option: C.
Mercury and carbon.
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MCQ 521 Mark
Dehydration of hydrates of halides of calcium, barium and strontium, i.e., $\mathrm{CaCl}_2 \cdot 6 \mathrm{H}_2 \mathrm{O}, \mathrm{BaCl}_2 \cdot 2 \mathrm{H}_2 \mathrm{O}, \mathrm{SrCl}_2 \cdot 2 \mathrm{H}_2 \mathrm{O}$, can be achieved by heating. These become wet oh keeping in air. Which of the following statements is correct about these halides?
  • A
    Act as dehydrating agents.
  • B
    Can absorb moisture from air.
  • ✓
    Tendency to form hydrate decreases from calcium to barium.
  • D
    All of the above.
Answer
Correct option: C.
Tendency to form hydrate decreases from calcium to barium.
Chlorides of alkaline earth metals are hydrated salts. Due to their hygroscopic nature, they can be used as dehydrating agents to absorb moisture from air.
Extent of hydration decreases from Mg to Ba, i.e., $\mathrm{MgCl}_2 \cdot 6 \mathrm{H}_2 \mathrm{O}, \mathrm{CaCl}_2 \cdot 6 \mathrm{H}_2 \mathrm{O}, \mathrm{BaCl}_2 2 \mathrm{H}_2 \mathrm{O}, \mathrm{SrCl}_2 \cdot 2 \mathrm{H}_2 \mathrm{O}$.
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MCQ 531 Mark
Which one of the following has a polarizing power close to that of $Mg$?
  • ✓
    $Li$
  • B
    $Na$
  • C
    $K$
  • D
    $Rb$
Answer
Correct option: A.
$Li$
$Li$ and $Mg$ shows diagonal relationship. They have nearly same polarizing power.
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MCQ 541 Mark
The characteristic not related to alkali metals is:
  • A
    Their ions are isoelectronic with noble gases.
  • B
    Metallic character.
  • C
    Low electronegativity.
  • ✓
    High ionization energy.
Answer
Correct option: D.
High ionization energy.
Alkali metals have low ionization energies due to their larger atomic radii.
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MCQ 551 Mark
The order of decreasing ionization enthalpy in alkali metals is:
  • A
    $\ce{Na > Li > K > Rb.}$
  • B
    $\ce{Rb < Na < K < Li.}$
  • ✓
    $\ce{Li > Na > K > Rb.}$
  • D
    $\ce{K < Li < Na < Rb.}$
Answer
Correct option: C.
$\ce{Li > Na > K > Rb.}$
Lonization enthalpy decreases with increase in Size of the atom in a group.
Hence, the order is:
$\ce{Li > Na > K > Rb.}$
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MCQ 561 Mark
Which of the following element participate in oxidation of glucose to form $\text{ATP}$?
  • A
    Calcium
  • B
    Sodium
  • C
    Magnesium
  • ✓
    Potassium
Answer
Correct option: D.
Potassium
Potassium participates in the oxidation of glucose to form $\text{ATP}$ through $\text{ATP-}$ sensitive potassium channel.
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MCQ 571 Mark
Along the group, size and ionisation enthalpy of the group $II$ elements respectively :
  • ✓
    Increases and decreases.
  • B
    Decreases and increases.
  • C
    Increases and increases.
  • D
    Decreases and decreases.
Answer
Correct option: A.
Increases and decreases.
Along the group, size of the group $II$ elements increases while ionisation enthalpy decreases.
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MCQ 581 Mark
The alkali metals are low melting. Which of the following alkali metal is expected to melt if the room temperature rises to $30^{\circ} C$?
  • A
    $Na$
  • B
    $K$
  • C
    $Rb$
  • ✓
    $Cs$
Answer
Correct option: D.
$Cs$
Among alkali metals, melting point decreases as the strength of metallic bonding decreases with increasing size of the atom. Thus, $Cs$ has the lowest melting point $(28.5^{\circ} C)$ and will melt at $30^{\circ} C$.
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MCQ 591 Mark
Fluorides and phosphates of alkali metals are:
  • A
    Completely soluble in water
  • B
    Sparingly soluble in water
  • ✓
    Completely soluble in water except $Li$ and $Mg$
  • D
    Completely insoluble in water except $Li$ and $Mg$
Answer
Correct option: C.
Completely soluble in water except $Li$ and $Mg$
Fluorides, phosphates of $Li$ and $Mg$ are sparingly soluble in water whereas those of other alkali metals are soluble in water.
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MCQ 601 Mark
Crude sodium chloride is generally obtained by crystallisation of:
  • ✓
    $\ce{NH_4Cl}$ solution.
  • B
    $\ce{NaOH}$ solution.
  • C
    Brine solution.
  • D
    None of these.
Answer
Correct option: A.
$\ce{NH_4Cl}$ solution.
Crude sodium chloride is generally obtained by crystallisation of brine solution.
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MCQ 611 Mark
The correct sequence of coralent character is represented by:
  • A
    $\ce{LiCl < NaCl < BeCl_2}$
  • B
    $\ce{BeCl_2 < LiCl < NaCl}$
  • ✓
    $\ce{NaCl < LiCl < BeCl_2}$
  • D
    $\ce{BeCl_2 < NaCl < LiCl}$
Answer
Correct option: C.
$\ce{NaCl < LiCl < BeCl_2}$
Smaller the cation, higher the charge, more will be tendency to form covalent compound.
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MCQ 621 Mark
When sodium is dissolved in liquid ammonia, a solution of deep blue colour is obtained. The colour of the solution is due to:
  • ✓
    Ammoniated electron.
  • B
    Sodium ion.
  • C
    Sodium amide.
  • D
    Ammoniated sodium ion.
Answer
Correct option: A.
Ammoniated electron.
The blue colour of the solution of alkali metals in liquid ammonia is due to the ammoniated electron which absorbs energy in the visible region of light and thus imparts blue colour to the solution.
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MCQ 631 Mark
Which is the major constituent of gun powder?
  • ✓
    Nitre
  • B
    Sulphur
  • C
    Charocal
  • D
    Chile salt petre
Answer
Correct option: A.
Nitre
Gunpowder is a mixture of sulphur, charcoal and potassium nitrate $($nitre$)$.
Among these Potassium Nitrate $($saltpeter$)$ is major constituent of gun powder.
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MCQ 641 Mark
Beryllium and magnesium are kinetically inert to oxygen and water because of the formation of :
  • ✓
    Oxide film on their surface.
  • B
    Hydroxide film on their surface.
  • C
    Hydrated salt.
  • D
    None of the above.
Answer
Correct option: A.
Oxide film on their surface.
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MCQ 651 Mark
Which of the following statement is correct?
  • ✓
    Lithium carbonate is soluble in water.
  • B
    Carbonates of $Ca$ and $Ba$ are soluble in water.
  • C
    Carbonates of $\mathrm{Na}^{+}, \mathrm{K}^{+}$and $\mathrm{NH}_4^{+}$are soluble in water.
  • D
    All the above.
Answer
Correct option: A.
Lithium carbonate is soluble in water.
Sodium carbonate, potassium carbonate and ammonium carbonate are soluble in water.
Metallic oxides are insoluble except for those of sodium and potassium which are very soluble and those of calcium, barium, strontium, and magnesium which are only slightly soluble.
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MCQ 661 Mark
lkaline earth metals act as:
  • ✓
    reducing agents
  • B
    oxidising agent
  • C
    amphoteric
  • D
    acidic
Answer
Correct option: A.
reducing agents
Alkaline earth metals are electropositive in nature and always undergo oxidation due to which the other reacting species undergo reduction and thus these metals act as reducing agents.
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MCQ 671 Mark
Which of the following choice$(s)$ correctly represent$(s)$ physical properties of alkali metals?
  • A
    They are silvery white coloured.
  • B
    They are soft.
  • C
    They are light metals.
  • ✓
    All of the above.
Answer
Correct option: D.
All of the above.
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MCQ 681 Mark
The close resemblance between the properties of an element of $2^{nd}$ period with those of the element of $3^{rd}$ period belonging to the next group is called:
  • A
    periodicity
  • B
    periodic trend
  • ✓
    diagonal relationship
  • D
    group trend
Answer
Correct option: C.
diagonal relationship
The close resemblance between the properties of an element of $2^{nd}$ period with those of the element of $3^{rd}$ period belonging to the next group is called diagonal relationship.
These pairs $($lithium and magnesium, beryllium and aluminium, boron and silicon etc.$)$ exhibit similar properties.
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MCQ 691 Mark
Which of the following represents an amphoteric hydroxide?
  • A
    $\text{Ca(OH)2}$
  • B
    $\text{Mg(OH)2}$
  • C
    $\text{Ba(OH)2}$
  • ✓
    $\text{Be(OH)2}$
Answer
Correct option: D.
$\text{Be(OH)2}$
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MCQ 701 Mark
A severe shortage of what in body fluids, may cause a potentially fatal condition known as hypokalemia?
  • A
    Sodium
  • ✓
    Potassium
  • C
    Iron
  • D
    Silicon
Answer
Correct option: B.
Potassium
Hypokalemia is when blood's potassium levels are too low. Potassium is an important electrolyte for nerve and muscle cell functioning, especially for muscle cells in the heart. Your kidneys control your body's potassium levels, allowing for excess potassium to leave the body through urine or sweat.
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MCQ 711 Mark
The enamel on teeth contains:
  • ✓
    Fluorapatite
  • B
    Chlorapatite
  • C
    Apatite
  • D
    Calcium monohydrogen phosphate
Answer
Correct option: A.
Fluorapatite
The enamel on teeth contains fluorapatite which is a phosphate mineral and contains calcium.
Its formula is $\mathrm{Ca}_5\left(\mathrm{PO}_4\right)_3 \mathrm{~F}$.
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MCQ 721 Mark
The alkali metals and their salts show characteristic colour to:
  • ✓
    An oxidising flame.
  • B
    A reducing flame.
  • C
    They don't show any colour to any flame.
  • D
    Both $(a)$ and $(b)$.
Answer
Correct option: A.
An oxidising flame.
Alkali metals and their salts impart characteristic colour to an oxidising flame. This is because heat from the flame excites the outermost electron to a higher energy level.
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MCQ 731 Mark
Which of the following mixtures is used as a flux in the extraction of metals?
  • A
    Calcium carbonate, strontium carbonate.
  • B
    Magnesium carbonate, calcium chloride.
  • ✓
    Calcium carbonate, magnesium carbonate.
  • D
    None of the above.
Answer
Correct option: C.
Calcium carbonate, magnesium carbonate.
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MCQ 741 Mark
The solubility of metal halides depends on their nature, lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals, the lowest solubility of $LiF$ in water is due to:
  • A
    Ionic nature of lithium fluoride.
  • ✓
    High lattice enthalpy.
  • C
    High hydration enthalpy for lithium ion.
  • D
    Low ionization enthalpy of lithium atom.
Answer
Correct option: B.
High lattice enthalpy.
Solubility of metal halides in water depends on lower lattice enthalpy and high hydration enthalpy. In case of $LiF$, the lowest solubility is due to its very high lattice enthalpy.
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MCQ 751 Mark
Which of the following imparts violet colouration to the Bunsen burner non-luminous flame?
  • A
    $\ce{NaCl}$
  • B
    $\ce{BaCl_2}$​
  • C
    $\ce{CaCl_2}$​
  • ✓
    $\ce{KCl}$
Answer
Correct option: D.
$\ce{KCl}$
Violet colouration to the Bunsen burner will be produced by potasium, so $\ce{KCl}$ imparts violet colouration to the Bunsen burner non$-$luminous flame.
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MCQ 761 Mark
The alkaline earth metal whose carbonate has no natural occurrence is :
  • A
    $Ba$
  • B
    $Ca$
  • C
    $Mg$
  • ✓
    $Be$
Answer
Correct option: D.
$Be$
Beryllium carbonate has no natural abundance.
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MCQ 771 Mark
Which of the following is not an important ingredient present in Portland cement?
  • A
    $ \mathrm{Ca}_2 \mathrm{SiO}_4 $
  • B
    $ \mathrm{Ca}_3 \mathrm{SiO}_5 $
  • C
    $ \mathrm{Ca}_3 \mathrm{Al}_2 \mathrm{O}_6 $
  • ✓
    $ \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2$
Answer
Correct option: D.
$ \mathrm{Ca}_3\left(\mathrm{PO}_4\right)_2$
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MCQ 781 Mark
The aqueous solutions of lithium salts are poor conductors of electricity as compared to that of other alkali metals because of:
  • A
    High ionization energy
  • B
    High electronegativity
  • C
    Lower ability of $\mathrm{Li}^{+}$ ions to polarize water molecules
  • ✓
    Higher degree of hydration of $\mathrm{Li}^{+}$ ions
Answer
Correct option: D.
Higher degree of hydration of $\mathrm{Li}^{+}$ ions
The aqueous solutions of lithium salts are poor conductors of electricity as compared to that of other alkali metals because of higher degree of hydration of $\mathrm{Li}^{+}$ ions.
It decreases the mobility and leads to low conductivity.
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MCQ 791 Mark
All the alkali metals have electronic configuration, $ns^1$ outside the noble gas core. They readily lose electron to give:
  • ✓
    Monovalent ions.
  • B
    Divalent ions.
  • C
    Trivalent ions.
  • D
    Both $(a)$ and $(b)$.
Answer
Correct option: A.
Monovalent ions.
Alkali metals have one valence electron $ns^1$ outside the noble gas core. So, they readily lose this electron to produce monovalent cation.
$\text{M}\xrightarrow{ \ \ \ \ \ \ \ \ }\text{M}^++\text{e}^-$
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MCQ 801 Mark
Molten sodium is used in nuclear reactors to :
  • A
    Absorb neutrons in order to control the chain reaction
  • B
    Slow down the fast neutrons
  • ✓
    Absorb the heat generated by nuclear fission
  • D
    Extract radio $-$isotopes produced in the reactor
Answer
Correct option: C.
Absorb the heat generated by nuclear fission
Molten sodium is used in nuclear reactors due to its high thermal conductivity properties, it is used as a coolant i.e. to absorb the heat produced during nuclear fission.
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MCQ 811 Mark
Nitrates of alkaline earth metals can be prepared by dissolution of:
  • A
    Hydroxides of alkaline earth metal in dilute nitric acid.
  • B
    Oxides of alkaline earth metal in dilute nitric acid.
  • ✓
    Carbonates of alkaline earth metal in dilute nitric acid.
  • D
    All of the above.
Answer
Correct option: C.
Carbonates of alkaline earth metal in dilute nitric acid.
Nitrates of alkaline earth metals are prepared by dissolution of carbonate of alkaline earth metals in dilute nitric acid.
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MCQ 821 Mark
Which of the following is used in radiotherapy?
  • A
    Barium salt.
  • B
    Calcium salt.
  • ✓
    Radium salt.
  • D
    Strontium salt.
Answer
Correct option: C.
Radium salt.
Radium salts are radioactive in nature hence they are used in radiotherapy.
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MCQ 831 Mark
Which of the following forms only covalent bonds with other elements?
  • A
    Calcium
  • B
    Barium
  • C
    Radium
  • ✓
    Beryllium
Answer
Correct option: D.
Beryllium
Beryllium's chemical behavior is largely a result of its small atomic and ionic radii. It thus has very high ionization potentials and strong polarization while bonded to other atoms, which is why all of itscompounds are covalent.
They form covalent bonds whereas the other members form of the group form ionic bonds.
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MCQ 841 Mark
Which of the following is the strongest reducing agent?
  • A
    $Be$
  • ✓
    $Ba$
  • C
    $Ca$
  • D
    $Mg$
Answer
Correct option: B.
$Ba$
Among the elements of alkaline earth metals, barium is the strongest reducing agent. On moving down the group, the atomic size increases.
The electropositive character increases and the ionization enthalpy value decreases.
Hence, reducing power also increases from $Be$ to $Ba.$
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MCQ 851 Mark
Above $373\  K$, the monohydrate sodium carbonate becomes completely anhydrous and called as :
  • A
    Potash ash.
  • ✓
    Soda ash.
  • C
    Pearl ash.
  • D
    Brine ash.
Answer
Correct option: B.
Soda ash.
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MCQ 861 Mark
If $X$ and $Y$ are the second ionisation potentials of alkali and alkaline earth metals of same period, then :
  • ✓
    $X > Y$
  • B
    $X < Y$
  • C
    $X = Y$
  • D
    $X << Y$
Answer
Correct option: A.
$X > Y$
The general electronic configuration of Alkali metal is $ns^1$ so if we remove first electron $($first ionization energy$)$ it will become octet configuration,so to remove next electron it requires more energy $($second ionization energy$)$ ,whereas the general electronic configuration of alkali earth metals is $ns^2$ so the electrons can be lost easily.,so the second ionization energy of alkali metal is more than the alkali earth metal,so the order of ionization energy is $X > Y$.
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MCQ 871 Mark
Dead burnt plaster is :
  • ✓
    $\text{CaSO}_4$
  • B
    $\text{CaSO}_4.\frac{1}{2}\text{H}_2\text{O}$
  • C
    $\text{CaSO}_4.\text{H}_2\text{O}$
  • D
    $\text{CaSO}_4.2\text{H}_2\text{O}$
Answer
Correct option: A.
$\text{CaSO}_4$
Plaster of paris is prepared b heating gypsum at $120^{\circ}C.$
$2\text{CaSO}_4.2\text{H}_2\text{O}\xrightarrow{\ \ \ \ }(\text{CaSO}_4)_2.\text{H}_2\text{O}+3\text{H}_2\text{O}\\\ \ \ \ \ \text{Gypsum}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Plaster of Paris}$
On heating plaster of paris at $200^{\circ}C$, it forms anhydrous calcium sulphate i.e., dead plaster which has no setting property as it absorbs water very slowly.
$\text{CaSO}_4.\frac{1}{2}\text{H}_2\text{O}\xrightarrow{200^\circ\text{C}}\text{CaSO}_4\xrightarrow{1100^\circ\text{C}}\text{CaO}+\text{SO}_3\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Anhydride}$
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MCQ 881 Mark
Which of the following is not a biological function of calcium?
  • A
    Neuromuscular function.
  • B
    Interneutronal transmission.
  • C
    Blood coagulation.
  • ✓
    Interstitial fluidity control.
Answer
Correct option: D.
Interstitial fluidity control.
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MCQ 891 Mark
The activity of alkaline earth metals as reducing agent :
  • A
    decreases from $Be$ to $Ba$
  • ✓
    increases from $Be$ to $Ba$
  • C
    increases from $Be$ to $Ca$ and decreases from $Ca$ to $Ba$
  • D
    decreases from $Be$ to $Ca$ and increases from $Ca$ to $Ba$
Answer
Correct option: B.
increases from $Be$ to $Ba$
The activity of alkaline earth metals as reducing agent increases from $Be$ to $Ba$ as it can easily lose the valence shell electrons.
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MCQ 901 Mark
The first ionization energies of alkaline earth metals are higher than those of the alkali metals. This is because:
  • ✓
    there is increase in the nuclear charge of the alkaline earth metal
  • B
    there is decrease in the nuclear charge of the alkaline earth metal
  • C
    there is no change in the nuclear charge
  • D
    none ofthe above
Answer
Correct option: A.
there is increase in the nuclear charge of the alkaline earth metal
As the nuclear charge increases it requires more energy to remove electron $($Ionization energy$)$ hence ionization energy will be increased. The first ionization energies of alkaline earth metals are higher than those of the alkali metals. This is because of the increase in the nuclear charge of the alkaline earth metal.
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MCQ 911 Mark
Alkali metal when exposed to air tarnish quickly due to the $.........$
  • A
    formation of their hydroxide
  • B
    formation of their carbonates
  • C
    formation of their oxides
  • ✓
    all the above
Answer
Correct option: D.
all the above
When exposed to air, the alkali metals tarnish quickly. This is because, they react with oxygen, moisture and carbon dioxide present in air to form oxides, hydroxides and carbonates.
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MCQ 921 Mark
The alkaline earth metals have smaller size than those of corresponding alkali metals. This is due to :
  • A
    Increase in ionisation enthalpy.
  • B
    Decrease in nuclear charge.
  • ✓
    Increase in nuclear charge.
  • D
    Increase in number of shells.
Answer
Correct option: C.
Increase in nuclear charge.
Smaller size of alkaline earth metal is due to high value of nuclear charge, which increases along a period from left to right.
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MCQ 931 Mark
What happens if we take excess intake of potassium?
  • A
    Hypokalemia
  • B
    Hypertension
  • ✓
    Hyperkalemia
  • D
    Low blood pressure
Answer
Correct option: C.
Hyperkalemia
Hyperkalemia is the medical term that describes a potassium level in your blood that's higher than normal.
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MCQ 941 Mark
Potassium hydroxide is a good conductor of an electric current in the:
  • A
    Gaseous state only
  • B
    Solid state only
  • C
    Solid and molten (fused) states
  • ✓
    Molten (fused) state and in aqueous solution
Answer
Correct option: D.
Molten (fused) state and in aqueous solution
Explanation: (D) Molten (fused) state and in aqueous solution
Potassium hydroxide is a good conductor of an electric current in the molten (fused) state and in aqueous solution. When it is in solid state it cannot conduct electricity but it can conduct electricity in aqueous solution state or molten state. This is because it is an ionic compound. Ionic compounds are made of charged ions which are held tightly in solid state but become mobile in molten or aqueous solution state. The movement of these mobile ions between electrodes helps in conducting electricity.
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MCQ 951 Mark
Which of the following metals is required as a cofactor by all enzymes utilizing  $\text{ATP}$ in phosphate transfer?
  • A
    $K$
  • B
    $Ca$
  • C
    $Na$
  • ✓
    $Mg$
Answer
Correct option: D.
$Mg$
$Mg$ binds to phosphate group in $\text{ATP}$ thus making a complex that catalyses phosphate transfer.
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MCQ 961 Mark
The metal used in solar cells is:
  • A
    $Na$
  • B
    $Li$
  • ✓
    $Cs$
  • D
    $Mg$
Answer
Correct option: C.
$Cs$
Among the given metals, Caesium $(Cs)$ has the lowest ionization enthalpy. Hence it loses electrons readily. Therefore, caesium is used in solar cells.
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MCQ 971 Mark
Which of the following statements is true about $\ce{Ca(OH)_2}$?
  • ✓
    It is used in the preparation of bleaching powder.
  • B
    It is a light blue solid.
  • C
    It does not possess disinfectant property.
  • D
    It is used in the manufacture of cement.
Answer
Correct option: A.
It is used in the preparation of bleaching powder.
$2\text{Ca}(\text{OH}_2)+2\text{Cl}_2\xrightarrow{\ \ \ \ }\text{CaCl}_2+\text{Ca}(\text{OCl})_2+\text{H}_2\text{O}\\\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \text{Bleaching powder}$
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MCQ 981 Mark
Which of the following has no reaction with water?
  • A
    $Ba$
  • B
    $Sr$
  • ✓
    $Be$
  • D
    $Mg$
Answer
Correct option: C.
$Be$
Beryllium does not react with water. This is due to the formation of protective thin layer of hydroxide on the surface of the metal.  
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MCQ 991 Mark
Which of the following elements does not form hydride by direct heating with dihydrogen?
  • ✓
    $Be$
  • B
    $Mg$
  • C
    $Sr$
  • D
    $Ba$
Answer
Correct option: A.
$Be$
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MCQ 1001 Mark
Which of the following imparts violet colouration to the Bunsen burner non$-$luminous flame?
  • A
    $\ce{NaCl}$
  • B
    $\ce{BaCl_2}$​
  • C
    $\ce{CaCl_2}$​
  • ✓
    $\ce{KCl}$
Answer
Correct option: D.
$\ce{KCl}$
Violet colouration to the Bunsen burner will be produced by potasium, so $\ce{KCl}$ imparts violet colouration to the Bunsen burner non$-$luminous flame.
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