Assertion : Alkyl isocyanides in acidified water give alkyl formamides.Reason : In isocyanides, carbon first acts as a nucleophile and then as an electrophile.

Alkyl isocyanides ($\text{RN}\equiv \text{C}$) undergo partial hydrolysis in acidified water to form $N$ -alkylformamides ($\text{RNHCHO}$). In the mechanism, the terminal carbon of the isocyanide group initially acts as a nucleophile to pick up a proton (${\text{H}}^{+}$) or react with an electrophile, and subsequently becomes an electrophilic center that is attacked by a nucleophile like water. Both assertion and reason are true, and the reason correctly explains the chemical reactivity leading to the product.