CBSE Class 11 Chemistry HOTs The S Block Elements

Question. Which of the following is not correct ?

Answer : A

Question. The stability of the following alkali metal chlorides follows the order
(a) LiCl > KCl > NaCl > CsCl
(b) CsCl > KCl > NaCl > LiCl
(c) NaCl > KCl > LiCl > CsCl
(d) KCl > CsCl > NaCl > LiCl
Answer : D

Question. The element which on burning in air gives peroxide is
(a) lithium
(b) sodium
(c) rubidium
(d) caesium
Answer : B

Question. Which property of sodium is being used in street lights ?
(a) It shows photoelectric effect
(b) It has low melting point
(c) Sodium atom emits photons in the yellow region of visible spectrum, due to electrically stimulated transitions
(d) Sodium vapours show golden colour
Answer : C

Question. Philosopher's wool on heating with BaO at 1100°C produces:
(a) Ba + ZnCl₂
(b) BaCdO₂
(c) BaZnO₂
(d) BaO₂+ Zn
Answer : C

Question. Sodium thiosulphate, Na₂S₂O₃. 5H₂O is used in photography to
(a) reduce the silver bromide grains to metallic silver
(b) convert the metallic silver to silver salt
(c) remove undecomposed AgBr as soluble silver thiosulphate complex.
(d) remove reduced silver
Answer : C

Question. Sodium sulphate is soluble in water whereas barium sulphate is sparingly soluble because
(a) the hydration energy of sodium sulphate is more than its lattice energy
(b) the lattice energy of sodium sulphate is equal to its hydration energy
(c) the hydration energy of sodium sulphate is less than its lattice energy
(d) None of these
Answer : A

Question. Which of the following statements about Na₂O₂ is not correct?
(a) It is diamagnetic in nature
(b) It is derivative of H₂O₂
(c) Na₂O₂ oxidises Cr³⁺ to CrO₄^2- in acid medium.
(d) It is the super oxide of sodium
Answer : D

Question. Metallic magnesium is prepared by
(a) reduction of MgO by coke
(b) electrolysis of aqueous solution of Mg(NO₃)₂
(c) displacement of Mg by iron from MgSO₄ solution
(d) electrolysis of molten MgCl₂
Answer : D

Question. Hesenclever ’s process is a method for the manufacture of
(a) NaOH
(b) HNO₃
(c) H₂SO₄
(d) Bleaching powder
Answer : D

Question. Which of the following compounds are paramagnetic in nature?
(a) KO₂
(b) K₂O₂
(c) Na₂O₂
(d) Rb₂O₂
Answer : A

Question. Causticisation is a process in which
(a) soap is prepared by treating vegetable oils with caustic soda
(b) paper is formed
(c) petroleum is treated with caustic soda before fractional distillation
(d) caustic soda is manufactured by treating sodium carbonate with lime.
Answer : D

Question. Lithopone is
(a) BaO + ZnSO₄
(b) BaS + ZnSO₄
(c) ZnS + BaSO₄
(d) ZnO + BaSO₄
Answer : C

Question. Equimolar solutions of the following compounds are prepared separately in water. Which will have the lowest pH value ?
(a) BeCl₂
(b) SrCl₂
(c) CaCl₂
(d) MgCl₂
Answer : A

Question. 100 mL of tap water containing Ca(HCO₃)₂ was titrated with N/50 HCl with methyl orange as indicator. If 30 mL of HCl were required, calculate the temporary hardness as parts of CaCO₃ per 106 parts of water.
(a) 150 ppm
(b) 300 ppm
(c) 450 ppm
(d) 600 ppm
Answer : B

Question. Which of the following sulphates have the highest solubility in water?
(a) MgSO₄
(b) BaSO₄
(c) CaSO₄
(d) BeSO₄
Answer : D

Question. An inorganic compound which on heating first melts, then solidifies and liberates O₂ gas, the inorganic compound is
(a) Al₂O₃
(b) KMnO₄
(c) MnO₂
(d) KClO₃
Answer : D

Question. Li has the maximum value of ionisation potential among alkali metals i.e. lithium has the minimum tendency to ionise to give Li⁺ ion. Thus, in aq. solution lithium is
(a) Strongest reducing agent
(b) Poorest reducing agent
(c) Strongest oxidising agent
(d) Poorest oxidising agent
Answer : A

Question. Thermal stability of alkaline earth metal carbonates decreases in order
(a) BaCO₃ > SrCO₃ > CaCO₃ > MgCO₃
(b) BaCO₃ > SrCO₃ > MgCO₃ > CaCO₃
(c) CaCO₃ > SrCO₃ > MgCO₃ > BaCO₃
(d) None of these
Answer : A

Question. Chemical A is used for water softening to remove temporary hardness. A reacts with Na₂CO₃ to generate caustic soda. When CO₂ is bubbled through A, it turns cloudly. What is the chemical formula of A
(a) CaCO₃
(b) CaO
(c) Ca(OH)₂
(d) Ca(HCO₃)₂
Answer : C

Question. Which one of the following salts does not impart colour to the flame ?
(a) KI
(b) LiCl
(c) CaCl₂
(d) MgCl₂
Answer : D

Question. Which of the following metal carbonate is decomposed on heating?
(a) MgCO₃
(b) Na₂CO₃
(c) K₂CO₃
(d) Rb₂CO₃
Answer : A

Question. Which of the following has correct increasing basic strength?
(a) MgO < BeO < CaO < BaO
(b) BeO < MgO < CaO < BaO
(c) BaO < CaO < MgO < BeO
(d) CaO < BaO < BeO < MgO
Answer : B

Question. Which of the following is used as a scavenger in metallurgy?
(a) Be
(b) Mg
(c) Ca
(d) Sr
Answer : C