CuSO₄ when reacts with KCN forms CuCN, which is insoluble in water. It is soluble in excess of KCN, due to formation of the following complex

Reaction BaO_2(g) $$\rightleftharpoons$$ BaO_(s) + O_2(g); $$\Delta $$H = +ve. In equilibrium condition, pressure of O₂ depends on

Which of the following has p$$\pi $$ $$-$$ d$$\pi $$ bonding?

In NO₃^$$-$$ ion number of bond pair and lone pair of electrons on nitrogen atom are