An active ingredient in bleaching powder that aids in the bleaching action is:

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

2.  ${\mathrm{CaO}}_2\mathrm{Cl}$

3.  ${\mathrm{CaCl}}_2$

4.  ${\mathrm{CaOCl}}_2$

Solubility of alkaline earth metal sulphates in water decreases in the sequence:

1. Mg > Ca > Sr >Ba
2. Ca > Sr > Ba > Mg
3. Sr > Ca > Mg > Ba
4. Ba > Mg > Sr > Ca

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

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. ${\mathrm{PbS}}_2{\mathrm{O}}_3$

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.

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. ${\mathrm{K}}_2{\mathrm{CO}}_3$

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.

The polarising power of Mg is close to that of –

1. Na                                       

2. Cs

3. Li                                         

4. K

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