Why does the reaction of 2-bromo-2-methylbutane and ethanolic solution of silver nitrate interfered by the presence of water in the sodium iodide in acetone reagent?

Question

(Substitution chemistry)

Thanks for any help!!

Answer 1

2-bromo-2-methybutane reacts with AgNO3 to form AgBr precipitate.

If NaI is present, it also reacts reacts with AgNO3 to form AgI precipitate.

When you observe the precipitate, how would you know what caused it?