Among the following, the essential amino acid is :

Which of the following statements is not true about partition chromatography?

A mixture containing the following four compounds is extracted with $$1M$$ $$HCl.$$ The compound that goes to aqueous layer is :

A metal ‘M’ reacts with nitrogen gas to afford ‘M₃N’. ‘M₃N’ on heating at high temperature gives back ‘M’ and on reaction with water produces a gas ‘B’. Gas ‘B’ reacts with aqueous solution of CuSO₄ to form a deep blue compound. ‘M’ and ‘B’ respectively are :