15.1.7—Rate of hydrolysis of halogenoalkanes

In hydrolysis, water or hydroxide replaces X in a halogenoalkane. A weaker C–X bond generally hydrolyses more readily, and aqueous silver nitrate detects the halide ion formed as AgX.

Keep the test fair: same concentration, temperature, solvent and volume. The precipitate time is evidence about relative rate, not a direct measurement of bond energy alone.

Iodoalkanes usually form AgI more quickly than bromo- or chloroalkanes because C–I cleavage is easier. The precipitate colour helps identify the halide.

A faster precipitate does not prove the reaction is purely SN1; substrate structure and nucleophile conditions also affect the rate.