Question

Arrange the following in order of increasing acid strength

(i) HBr, HCl , HF , HI

(ii) CH₄ , H₂O , HF ,NH₃

Answer 1

Acid strength is the measure of how easily the compound ionises or loses H⁺ ion.

1) In case of Haloacids, breaking of the H-X bond determines the acid strength.
The order of acid strength is as follows:
HF < HCl < HBr < HI

2) In case of the mentioned stability of conjugate base after loss of proton is important.
Thus the order will be
NH₃ < CH₄ < H₂O < HF