Question

As the number of $-OH$ groups increases in hypophosphorous acid, phosphorous acid, and phosphoric acid, the acidic strength:

• A. increases
• B. decreases
• C. remains nearly same
• D. remains appropriately same

Answer 1

The correct option is C remains nearly same

Although the number of $-OH$ groups is increasing in $H_{3}P{O}_4(3OH$ group), yet acidity does not increase much. This is due to the fact that the number of unprotonated oxygen, responsible for the enhancement of acidity due to the inductive effect, remains the same, as a result, dissociation constant also remain nearly the same.