Important Questions From S Block Elements For Class 11

(1) Dehydration of hydrates of halides of calcium, barium and strontium i.e., CaCl₂6H₂O, BaCl₂.2H₂O, SrCl₂.2H₂O, can be achieved by heating. These become wet on keeping in air. Which of the following statements is correct about these halides?

[A] act as dehydrating agent

[B] can absorb moisture from air

[C] Tendency to form hydrate decreases from calcium to barium

[D] All of the above

Answer: All of the above

(2) Metallic elements are described by their standard electrode potential, fusion enthalpy, atomic size, etc. The alkali metals are characterised by which of the following properties?

[A] High boiling point

[B] High negative standard electrode potential

[C] High density

[D] Large atomic size

Answer: B, D

(3) Several sodium compounds find use in industries. Which of the following compounds are used for textile industry?

[A] Na₂CO₃

[B] NaHCO₃

[C] NaOH

[D] NaCl

Answer: A, C

(4) Which of the following compounds are readily soluble in water?

[A] BeSO₄

[B] MgSO₄

[C] BaSO₄

[D] SrSO₄

Answer: A, B

(5) When Zeolite, which is hydrated sodium aluminium silicate is treated with hard water, the sodium ions are exchanged with which of the following ion(s)?

[A] H⁺ ions

[B] Mg²⁺ ions

[C] Ca²⁺ ions

[D]

Answer: B, C

(6) Identify the correct formula of halides of alkaline earth metals from the following.

[A] BaCl₂.2H₂O

[B] BaCl₂.4H₂O

[C] CaCl₂.6H₂O

[D] SrCl₂.4H₂O

Answer: A, C

(7) Choose the correct statements from the following.

[A] Beryllium is not readily attacked by acids because of the presence of an oxide film on the surface of the metal.

[B] Beryllium sulphate is readily soluble in water as the greater hydration enthalpy of Be²⁺ overcomes the lattice enthalpy factor.

[C] Beryllium exhibits coordination number more than four.

[D] Beryllium oxide is purely acidic in nature.

Answer: A, B

(8) Which of the following are the correct reasons for anomalous behaviour of lithium?

[A] Exceptionally small size of its atom

[B] Its high polarising power

[C] It has high degree of hydration

[D] Exceptionally low ionisation enthalpy

Answer: A, B

(9) Assertion (A): The carbonate of lithium decomposes easily on heating to form lithium oxide and CO₂.

Reason (R) : Lithium being very small in size polarises large carbonate ion leading to the formation of more stable Li₂O and CO₂.

[A] Both A and R are correct and R is the correct explanation of A.

[B] Both A and R are correct but R is not the correct explanation of A.

[C] Both A and R are not correct

[D] A is not correct but R is correct.

Answer: Both A and R are correct and R is the correct explanation of A.

(10) Assertion (A): Beryllium carbonate is kept in the atmosphere of carbon dioxide.

Reason (R) : Beryllium carbonate is unstable and decomposes to give beryllium oxide and carbon dioxide.

[A] Both A and R are correct and R is the correct explanation of A.

[B] Both A and R are correct but R is not the correct explanation of A.

[C] Both A and R are not correct.

[D] A is not correct but R is correct.

Answer: Both A and R are correct and R is the correct explanation of A.

(11) Find the incorrect trend for alkaline earth metals

[A] atomic size Be < Mg < Ca < Sr

[B] second ionization energy Be < Mg < Ca < Sr

[C] Hydration enthalpy Sr < Ca < Mg < Be

[D] Density Ca < Mg < Be < Sr

Answer: second ionization energy Be < Mg < Ca < Sr

(12) Which one is known as a fusion mixture?

[A] Na₂CO₃ + NaHCO₃

[B] Na₂CO₃ + NaOH

[C] Na₂CO₃ + K₂SO₄

[D] Na₂CO₃ + K₂CO₃

Answer: Na₂CO₃ + K₂CO₃

(13) The tendency to lose their valance electron easily by alkali metals makes them

[A] strong reducing agent

[B] weak reducing agent

[C] strong oxidising agent

[D] weak oxidising agent

Answer: strong reducing agent

(14) Be shows the diagonal relationship with

[A] Na

[B] Al

[C] Mg

[D] B

Answer: Al

(15) Which oxide is amphoteric?

[A] BaO

[B] CaO

[C] BeO

[D] MgO

Answer: BeO

(16) Plaster of Paris (POP) is

[A] CaSO₄H₂O

[B] CaSO₄2H₂O

[C] CaSO₄

[D] CaSO₄1/2H₂O

Answer: CaSO₄1/2H₂O

(17) Which one is the most stable carbonate?

[A] BaCO₃

[B] MgCO₃

[C] CaCO₃

[D] BeCO₃

Answer: BaCO₃

(18) As compared to K, Na has

[A] higher ionization potential

[B] lower melting point

[C] lower electronegativity

[D] larger atomic radius

Answer: higher ionization potential

(19) Which of the ions have maximum hydration energy?

[A] Sr²⁺

[B] Ca²⁺

[C] Mg²⁺

[D] Be²⁺

Answer: Be²⁺

(20) Which of the compounds is known as Slaked lime?

[A] CaO

[B] CaSO₄

[C] Ca(OH)₂

[D] CaCO₃

Answer: Ca(OH)₂

Important Questions From S Block Elements For Class 11

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