Alkaline earth metals form hydrated crystalline solids such as $MgC{l}_2.6H_{2}O, CaC{l}_2.6H_{2}O$. This is due to-

(1) Smaller ionic size

(2) Increased charge on ions

(3) Higher hydration enthalpies

(4) High oxidation potential

The commercial salt is purified by passing-

(1) $H_{2}S$ gas through an alkaline solution of salt

(2) HCl gas through a saturated solution of salt

(3) $H_2$ gas through a solution of salt

(4) $C{l}_2$ gas through a saturated solution of salt

The incorrect statement among the following is-

1. Alkali metals are more electropositive than alkaline earth metals.

2. Alkaline earth metals are denser and harder than alkali metals.

3. An alkali metal's electronic configuration is ns¹ and an alkaline earth metal's electronic configuration is ns²

4. The first IP of alkali metals is more than that of alkaline earth metals.

Potassium is kept-

1. Under cold water.                                 

2. In ammonia.

3. In alcohol.                                         

4. In kerosene.

KOH can be prepared- 

(1) By the electrolysis of potassium chloride solution

(2) By the action of barium hydroxide on potassium sulphate

(3) By the action of lime on potassium chloride

(4) By the action of lime on potassium carbonate.

Magnesium can be prepared by heating-

(1) $MgC{l}_2$ with CaO at 1775 K

(2) $MgC{l}_2$ with $Ca{C}_2$ at 1775 K

(3) $MgC{l}_2$ with $Ca{\left(OH\right)}_2$ under pressure

(4) MgO with $Ca{C}_2$ at ordinary temperature

Nitrolim (a nitrogenous fertilizer) is a mixture of-

1. Calcium carbide and calcium cyanamide.

2. Calcium oxide and calcium carbide.

3. Calcium cyanamide and carbon.

4. Calcium oxide and carbon.

The strongest base among the following is-

1. $\mathrm{Al}{\left(\mathrm{OH}\right)}_3$                                   

2. $\mathrm{Mg}{\left(\mathrm{OH}\right)}_2$

3. $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$                                 

4. $\mathrm{Ba}{\left(\mathrm{OH}\right)}_2$

When magnesium ribbon is heated to redness in an atmosphere of nitrogen and subsequently cooled with water, the gas evolved is-

(1) $N_2$                                               

(2) $N{H}_3$

(3) $H_2$                                               

(4) $C{O}_2$

The ion of which of the following metals has least ionic conductivity in the aqueous solution-

(1) Lithium                                           

(2) Sodium 

(3) Potassium                                         

(4) Rubidium