The composition of 'Golden spangles' is

$Al_4C_3$ is an ionic carbide,named as

Match the following compounds (Column-$I$) with their uses (Column-$II$):

Column-$I$	Column-$II$
$I. Ca(OH)_2$	$A$. Casts of statues
$II. NaCl$	$B$. White wash
$III. CaSO_4 \cdot \frac{1}{2}H_2O$	$C$. Antacid
$IV. CaCO_3$	$D$. Washing soda preparation

$A$ metal $M$ and its compound can give the following observable changes in a sequence of reactions: $M$ $\xrightarrow{\text{dilute } HNO_3} \text{Colourless solution}$ $\xrightarrow{\text{aqueous } NaOH} \text{White precipitate}$ $\xrightarrow{\text{excess } NaOH_{(aq)}} \text{Colourless solution}$ $\xrightarrow{H_2S} \text{White precipitate}$. Identify the metal $M$.

The pair$(s)$ of reagents that yield paramagnetic species is/are:
$A$. $Na$ and excess of $NH_3$
$B$. $K$ and excess of $O_2$
$C$. $Cu$ and dilute $HNO_3$
$D$. $O_2$ and $2-ethylanthraquinol$

The correct order of solubility in water is: