Which of the following hydrides is electron-deficient?

Sodium forms a crystalline ionic solid with dihydrogen. The solid is non-volatile and non-conducting in nature. It reacts violently with water to produce dihydrogen gas. Write the formula of this compound and its reaction with water. What will happen on electrolysis of the melt of this solid?

The hydrides of which group elements are examples of electron-precise hydrides?

What do you expect the nature of hydrides is,if formed by elements of atomic numbers $15, 19, 23$ and $44$ with dihydrogen? Compare their behaviour towards water.

Pure hydrogen is obtained by carrying out the electrolysis of:

If a mole of $H_2$ molecules is heated to a high temperature,which of the following reactions takes place?