Explain why can alkali and alkaline earth metals not be obtained by chemical reduction methods?

202.

Why are potassium and caesium, rather than lithium used in photoelectric cells?

Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals. (a) Nitrates (b) Carbonates (c) Sulphates. 

Starting with sodium chloride how would you proceed to prepare (i) sodium metal (ii) sodium hydroxide (iii) sodium peroxide (iv) sodium carbonate?

Describe the importance of the following: (i) limestone (ii) cement (iii) plaster of paris.

Amongst the following, select the element having highest ionization enthalpy.

• Sodium

• Potassium

• Beryllium

• Magnesium

The main oxides formed on combustion of Li, Na and K in excess of air are, respectively:

• LiO₂, Na₂O₂ and K₂O

• LiO₂, Na₂O₂ and KO₂

• LiO, Na₂O₂ and KO₂

• LiO, Na₂O₂ and KO₂

Which one of the following alkaline earth metal sulphates has its hydration enthalpy greater than its lattice enthalpy?

• CaSO₄

• BeSO₄

• BaSO₄

• BaSO₄

The correct statement for the molecule, CsI₃ is 

• It is a covalent molecules

• It contains Cs⁺ and I₃^-

• It contains Cs³⁺ and I^- ions

• It contains Cs³⁺ and I^- ions

Which of the following on thermal decomposition yields a basic as well as an acidic oxide?

• NaNO₃

• KClO₃

• CaCO₃

• CaCO₃