Hot concentrated sulphuric acid on reaction with which one of the following elements,produces two gaseous products?

Bleaching powder is obtained by the action of chlorine on which of the following?

$A$ red solid is insoluble in water. However,it becomes soluble if some $KI$ is added to water. Heating the red solid in a test tube results in the liberation of violet-coloured fumes and droplets of a metal appear on the cooler parts of the test tube. The red solid is:

Which gas burns with a blue flame?

Which one of the following is correct about the stability of the given ions?

In the following reaction,identify the nature of the product formed by the complete hydrolysis of the underlined atom at $R.T.$:
$\underline{S}O_3 + H_2O \longrightarrow H_2SO_4$