What is the boiling point of heavy water (in $^{\circ} C$)?

Select the correct statement about water.
$(i)$ Critical temperature of $H_2O$ is less than $NH_3$.
$(ii)$ Standard boiling point of water is $100 \ ^oC$.
$(iii)$ Critical volume of $H_2O$ is less than $NH_3$.

Hydrolysis of which of the following compounds liberates an acidic gas?

The substance used as a universal solvent is .....

Match List $I$ with List $II$ and select the correct answer using the codes given below the lists:

$1.$ Heavy water	$a.$ Bicarbonates of $Mg$ and $Ca$ in water
$2.$ Temporary hard water	$b.$ No foreign ions in water
$3.$ Soft water	$c.$ $D_2O$
$4.$ Permanent hard water	$d.$ Sulphates and chlorides of $Mg$ and $Ca$ in water

Match the following:

List-$I$ (Reactions)	List-$II$ (Methods)
$A$. $Mg(HCO_3)_2 \rightarrow Mg(OH)_2 \downarrow + 2 CO_2 \uparrow$	$I$. Clark's method
$B$. $M^{2+} + Na_4P_6O_{18}^{2-} \rightarrow [Na_2MP_6O_{18}]^{2-} + 2 Na^{+}$	$II$. Ion exchange method
$C$. $Ca(HCO_3)_2 + Ca(OH)_2 \rightarrow 2 CaCO_3 + 2 H_2O$	$III$. Boiling
$D$. $2 NaZ + Ca^{2+}_{(aq)} \rightarrow 2 Na^{+} + CaZ_2$ ($Z$ = Zeolite)	$IV$. Calgon's method