An aqueous solution of a colourless metal sulphate $M$ gives a white precipitate with $NaOH$. This precipitate is soluble in excess of $NaOH$. On passing $H_2S$ through this solution,a white precipitate is formed. The metal $M$ in the salt is:

Give the correct order of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.
$(I)$ Number of $S-S$ bonds in $H_{2}S_{n}O_{6}$ is $(n - 1)$.
$(II)$ When $F_{2}$ reacts with water,it gives $HF, O_{2}$ and $O_{3}$.
$(III)$ $LiNO_{3}$ and $BaCl_{2}$ compounds are used in fireworks.
$(IV)$ $Be$ and $Mg$ hydrides are ionic and polymeric.

$A$ red coloured mixed oxide $(X)$ on treatment with conc. $HNO_3$ gives a compound $(Y).$ $(Y)$ with $HCl$ produces a chloride compound $(Z)$ which can also be produced by treating $(X)$ with conc. $HCl.$ Compounds $(X),$ $(Y),$ and $(Z)$ will be

Which of the following statements are false?

Green vitriol is . . . .

Match column-$I$ with column-$II$ :

column-$I$	column-$II$
$a$. $Ra$	$p$. Aeroplane industry
$b$. $K$	$q$. Down cell
$c$. $Li$	$r$. Photo electric cell
$d$. $Na$	$s$. Radioactive