What is the nature of metal nitrates?

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:

Bleaching powder is a compound having the molecular formula

In which of the following is a metal-to-metal bond present?

Match the following:

Metal	Uses
$1$. Sodium	$a$. For preparing springs
$2$. Beryllium-copper	$b$. In treatment of cancer
$3$. Radium	$c$. In preparation of aeroplanes
$4$. Magnesium-aluminium	$d$. In color industries

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A$. Chlorophyll	$I$. $Na_2CO_3$
$B$. Soda ash	$II$. $CaSO_4$
$C$. Dentistry,Ornamental work	$III$. $Mg^{2+}$
$D$. Used in white washing	$IV$. $Ca(OH)_2$

Choose the correct answer from the options given below: