An alloy which does not contain copper is

$A$ white solid '$A$' on heating produces a gas that turns lime water milky,and the remaining solid residue is yellow when hot but turns white on cooling. The solid '$A$' is:

Compare the solubility and thermal stability of the following compounds of the alkali metals with those of the alkaline earth metals: $(i)$ Nitrates,$(ii)$ Carbonates,$(iii)$ Sulphates.

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. $Na_2CO_3 \cdot 10H_2O$	$I$. $Caustic \ soda$
$B$. $NaOH$	$II$. $Slaked \ lime$
$C$. $Ca(OH)_2$	$III$. $Baking \ soda$
$D$. $NaHCO_3$	$IV$. $Washing \ soda$

The correct order of solubility in water is:

Match the following compounds in Column-$I$ with their products of heating effect in Column-$II$:

Column-$I$ (Compound)	Column-$II$ (Products of heating effect)
$a$. $LiNO_3$	$P$. Metal oxide
$b$. $FeSO_4 \cdot 7H_2O$	$Q$. Paramagnetic gas
$c$. $NaHCO_3$	$R$. Acidic gas
$d$. $BeCO_3$	$S$. Evolved gas has same number of $\sigma$ and $\pi$ bonds