The element which is the most abundant in the earth's crust is

Bleaching action of $SO_2$ is due to

When a colorless gas is passed through bromine water and it causes decolorization,which gas is it?

Assertion : Dinegative anion of oxygen $(O^{2-})$ is quite common but dinegative anion of sulphur $(S^{2-})$ is less common.
Reason : Covalency of oxygen is two.

Write the order of thermal stability of the hydrides of Group $16$ elements.

Oxygen is not evolved on reaction of ozone with