Ionic mobility of which of the following alkali metal ions is lowest when aqueous solution of their salts are put under an electric field?
1. K
2. Rb
3. Li
4. Na

Which one of the following process will produce hard water

1. Saturation of water with ${\mathrm{CaSO}}_4$

2. Addition of ${\mathrm{Na}}_2{\mathrm{SO}}_4$ to water

3. Saturation of water with ${\mathrm{CaCO}}_3$

4. Saturation of water with ${\mathrm{MgCO}}_3$

When zeolite (hydrated sodium aluminium silicate) is treated with hard water, the sodium ions are exchanged with

1. ${\mathrm{H}}^{+}$ ions

2. ${\mathrm{Ca}}^{2+}$ions

3. ${\mathrm{SO}}_4^{2-}$ ions

4. ${\mathrm{OH}}^{-}$ ions 

Calgon ( a water softener) is

1. ${\mathrm{Na}}_2\left[{\mathrm{Na}}_4{\left({\mathrm{PO}}_3\right)}_6\right]$

2. ${\mathrm{Na}}_4{\left[{\mathrm{Na}}_2\left({\mathrm{PO}}_3\right)\right]}_6$

3. ${\mathrm{Na}}_2{\left[{\mathrm{Na}}_4\left({\mathrm{PO}}_4\right)\right]}_6$

4. ${\mathrm{Na}}_4{\left[{\mathrm{Na}}_2\left({\mathrm{PO}}_4\right)\right]}_6$

Temporary hardness is caused due to presence of 

1. ${\mathrm{CaSO}}_4$

2. ${\mathrm{CaCl}}_2$

3. ${\mathrm{CaCO}}_3$

4. $\mathrm{Ca}{\left({\mathrm{HCO}}_3\right)}_2$

The compound (s) formed upon combustion of sodium metal in excess air is (are)

1. ${\mathrm{Na}}_2{\mathrm{O}}_2$

2. ${\mathrm{Na}}_3\mathrm{N}$

3. ${\mathrm{NaO}}_2$

4. NaOH

Which of the following statements are false ?

1. ${\mathrm{BeCl}}_2$ is a linear molecule in the vapour state
    but it is polymeric form in the solid state

2. Calcium hydride is called hydrolith

3. Carbides of both Be and Ca react with water
    to form acetylene

4. Oxides of both Be and Al are amphoteric 

The commercial method of preparation of potassium by reduction of molten KCl with metallic sodium at 850°C is based on the fact that -

1. Potassium is solid and sodium distils off at 850 °C.

2. Potassium is more volatile and distils off thus shifting the reaction forward.

3. Sodium is more reactive than potassium at 850 °C.

4. Sodium has less affinity to chloride ions in the presence of potassium ions.

The aqueous solutions of lithium salts
are poor conductor of electricity rather
than other alkali metals because of 

1. high ionisation energy

2. high electronegativity

3. lower ability of ${\mathrm{Li}}^{+}$ ions to 
    polarize water molecules

4. higher degree of hydration of 
    ${\mathrm{Li}}^{+}$ ions