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

Which has highest pH?

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