Alkyl halide reaction with AgNO₃(aq) via nucleophilic substitution and precipitate color

Steps:

• Identify CH₃I as a primary alkyl iodide reacting with AgNO₃(aq) to test for the halide ion.
• The mechanism is nucleophilic substitution, where Ag⁺ coordinates with I⁻, promoting departure and forming AgI precipitate.
• At 50°C in water, the reaction proceeds, yielding a colored precipitate characteristic of the halide.
• For iodide, AgI forms as a yellow solid, distinguishing it from other halides.

Why D is correct:

• Alkyl halides like CH₃I undergo nucleophilic substitution; AgI precipitate is yellow, as per standard halide test colors.

Why the others are wrong:

• A and B: Electrophilic substitution applies to aromatic compounds, not alkyl halides.
• C: Nucleophilic substitution is correct, but AgI is yellow, not cream (cream is for AgCl or AgBr).

Final answer: D