The gas evolved when methylamine reacts with nitrous acid is __________.

• When methylamine reacts with nitrous acid (prepared in situ by reaction of mineral acid and sodium nitrite) and forms an intermediate aliphatic diazonium salt which is being unstable readily forms alcohol and evolution of nitrogen gas occurs simultaneously . for this reason this reaction is used in estimation of amino acids and proteins.

• Other 3 options i), (iii) and iv) is not possible for this reaction.