Dissociation constant values for H ₂ CO ₃ , CH ₃ COOH , HCN, and HF are 4.3 10⁻⁷ , 1.8 10⁻⁵ , 4.0 10⁻¹⁰ and 7.2 10⁻⁴ respectively, at 25^ C . Identify the correct order of their increasing acid strength.

Step-by-step solution

Acid strength is directly proportional to the dissociation constant K_a . Given K_a values are: K_a( HCN ) = 4.0 10⁻¹⁰ K_a( H ₂ CO ₃) = 4.3 10⁻⁷ K_a( CH ₃ COOH ) = 1.8 10⁻⁵ K_a( HF ) = 7.2 10⁻⁴ Arranging the K_a values in increasing order: 4.0 10⁻¹⁰ Therefore, the increasing order of acid strength is: HCN Answer: HCN < H ₂ CO ₃ < CH ₃ COOH < HF