The element which does not belong to group $15$ is

Oxygen is more electronegative than sulphur,yet $H_2S$ is acidic in nature while $H_2O$ is neutral. This is because:

For the preparation of sodium thiosulphate by the "Springs reaction",the reactants used are

Which of the following elements is $NOT$ a member of group $16$ of the periodic table?

Why is a Tyndall box used in the manufacture of sulfuric acid by the contact process?

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.