What is the action of nitrous acid on primary nitroalkane?
Reaction with nitrous acid: The reaction is used to distinguish between primary, secondary or tertiary nitroalkanes. With nitrous acid, α-hydrogen is replaced by nitroso group.
a. Primary nitroalkanes react with nitrous acid to form blue coloured nitroso-nitroalkanes (aci form) which on dissolution in sodium hydroxide gives red solution.