why is sulphuric acid not used during the reaction of alcohols with KI - Chemistry - Haloalkanes and Haloarenes

Question

why is sulphuric acid not used during the reaction of alcohols
with KI?

Kumar Sarang · Accepted Answer

When alcohol is treated with KI in presence of sulfuric acid the reaction occurs as follows :

STEP 1: $2 K I + H_{2} S O_{4} \to 2 K H S O_{4} + 2 H I$

Thus the KI produces HI.

STEP 2: Now the alcohol has to react with HI to produce alkyl iodide but sulfuric acid being an oxidizing agent oxidizes HI to produce $I_{2}$ as follows :

$2 H I + H_{2} S O_{4} \to I_{2} + S O_{2} + H_{2} O$

Thus the reaction between HI and alcohol could not occur.

thus alcohol is treated with KI presence of non oxidizing acids such as phosphoric acid

why is sulphuric acid not used during the reaction of alcohols with KI?