The polarising power of Mg is close to that of –

1. Na                                       

2. Cs

3. Li                                         

4. K

A blue coluored solution of an alkali metal in liq NH₃ is due to the presence of -

1. ${\mathrm{M}}^{-}$atoms.                                         

2. ${\mathrm{M}}^{+}$ ions .

3. Solvated anions  .                           

4. Solvated electrons.

A compound X on heating gives a colourless gas. The residue is dissolved in water to obtain Y. Excess $C{O}_2$ is bubbled through an aqueous solution of Y, and Z is formed. Z on gentle heating gives back X. The compound X is-

1. ${\mathrm{CaCO}}_3$                                           

2. ${\mathrm{Na}}_2{\mathrm{CO}}_3$

3. ${\mathrm{CaSO}}_4.2{\mathrm{H}}_2\mathrm{O}$                                 

4. ${\mathrm{K}}_2{\mathrm{CO}}_3$

Magnesia can be prepared by -

1. Burning Mg in air.

2. Heating hydroxide, nitrate, sulphate or carbonate of magnesium.

3. Heating Mg in steam.

4. All of the above.

The incorrect statement among the following regarding Lithium is that-

1. The hydroxide, carbonate and nitrate decompose to give the oxide on heating.

2. It is the most electronegative element of group IA.

3. The hydrogen carbonate cannot be isolated as a stable solid.

4. It forms superoxide.

An amphoteric oxide among the following is-

1. CaO                                                     

2. SrO

3. BeO                                                     

4. MgO

The number of crystal water in Gypsum, Plaster of Paris and Epsom salt respectively are-

1. 2, 0.5, 7                                             

2. 7, 2, 1

3. 7, 0.5, 2                                             

4. 3, 4, 2

The correct relation about the density of Na and K is 

1. Na > K                                                     

2. Na = K

3. K > Na                                                     

4. Li > K

$\left(\mathrm{Yellow} \mathrm{ppt}\right)\stackrel{{\mathrm{K}}_2{\mathrm{CrO}}_4}{\leftarrow }\mathrm{X}\stackrel{\mathrm{dil}. \mathrm{HCl}}{\to }$
$\left(\mathrm{Yellow} \mathrm{ppt}\right) +\mathrm{Z}\uparrow (\mathrm{pungent} \mathrm{smelling} \mathrm{gas})$

If X gives a green flame test, then X is:

1. ${\mathrm{MgSO}}_4$

2. ${\mathrm{BaS}}_2{\mathrm{O}}_3$

3. ${\mathrm{CuSO}}_4$

4. ${\mathrm{PbS}}_2{\mathrm{O}}_3$

A compound (A) is used in the preparation of washing soda to recover ammonia in Solvay's process. When CO₂ is bubbled through an aqueous solution of (A), the solution turns milky. It is used in whitewashing due to its disinfectant nature. The chemical formula of A is : 

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

2. CaO

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

4. ${\mathrm{CaCO}}_3$