Which one of the following removes temporary hardness of water?

Match the following methods for treating hardness of water with their corresponding reagents used.

List-$I$	List-$II$
$A$. Treatment with washing soda	$I$. $Ca(OH)_2$
$B$. Calgon's method	$II$. $Na_2CO_3$
$C$. Clark's method	$III$. $NaAlSiO_4$
$D$. Zeolite/permutit process	$IV$. $Na_6P_6O_{18}$

The correct match is:

What is 'plumbo solvency' referring to in the context of lead?

Assertion $(A)$ : $NaCl$ is less soluble in heavy water than in ordinary water.
Reason $(R)$ : Dielectric constant of ordinary water is more than that of heavy water.
The correct answer is

At atmospheric pressure and very low temperature,water crystallises to

Identify the correct statements from the following.
$A$. In photosynthesis reaction,water is oxidized to oxygen.
$B$. An example for interstitial hydride is $MgH_2$.
$C$. Sodium hexametaphosphate is used in the removal of permanent hardness of water.