Why Alchohol Doesnt React with NaI Or KI 2 Form R-I , But Reacts with HI 2 Form R-I ??

Answer 1

When using HI, the hydroxy group is protonated, producing water, which is a much better leaving group than -OH is. Iodide on its own is not strong enough as a nucleophile to displace -OH, but it will react with a carboncation produced from the protonation of an alcohol.