Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
MHT CET 202621 AprilEvening Shift
Exam
MHT CET
Year
2026
Date
21 April
Shift
Evening Shift
Subject
Chemistry
Chapter
Ionic Equilibrium

MHT CET 2026 · 21 April · Evening Shift · Chemistry · Ionic Equilibrium

Dissociation constant values for H_2CO_3 , CH_3COOH , HCN, and HF...

Dissociation constant values for H2CO3\text{H}_2\text{CO}_3, CH3COOH\text{CH}_3\text{COOH}, HCN, and HF are 4.3×10−74.3 \times 10^{-7}, 1.8×10−51.8 \times 10^{-5}, 4.0×10−104.0 \times 10^{-10} and 7.2×10−47.2 \times 10^{-4} respectively, at 25^{}^{\circ}\text{C}. Identify the correct order of their increasing acid strength.

Options

  1. AHF<CH3COOH<H2CO3<HCN\text{HF} < \text{CH}_3\text{COOH} < \text{H}_2\text{CO}_3 < \text{HCN}
  2. BHCN<H2CO3<CH3COOH<HF\text{HCN} < \text{H}_2\text{CO}_3 < \text{CH}_3\text{COOH} < \text{HF}
  3. CHCN<HF<H2CO3<CH3COOH\text{HCN} < \text{HF} < \text{H}_2\text{CO}_3 < \text{CH}_3\text{COOH}
  4. DCH3COOH<H2CO3<HF<HCN\text{CH}_3\text{COOH} < \text{H}_2\text{CO}_3 < \text{HF} < \text{HCN}

Correct answer

B. HCN<H2CO3<CH3COOH<HF\text{HCN} < \text{H}_2\text{CO}_3 < \text{CH}_3\text{COOH} < \text{HF}

Step-by-step solution

Acid strength is directly proportional to the dissociation constant KaK_a.

Given KaK_a values are:
Ka(HCN)=4.0×10−10K_a(\text{HCN}) = 4.0 \times 10^{-10}
Ka(H2CO3)=4.3×10−7K_a(\text{H}_2\text{CO}_3) = 4.3 \times 10^{-7}
Ka(CH3COOH)=1.8×10−5K_a(\text{CH}_3\text{COOH}) = 1.8 \times 10^{-5}
Ka(HF)=7.2×10−4K_a(\text{HF}) = 7.2 \times 10^{-4}

Arranging the KaK_a values in increasing order:
4.0×10−10<4.3×10−7<1.8×10−5<7.2×10−44.0 \times 10^{-10} < 4.3 \times 10^{-7} < 1.8 \times 10^{-5} < 7.2 \times 10^{-4}

Therefore, the increasing order of acid strength is:
HCN<H2CO3<CH3COOH<HF\text{HCN} < \text{H}_2\text{CO}_3 < \text{CH}_3\text{COOH} < \text{HF}

Answer: HCN<H2CO3<CH3COOH<HF\text{HCN} < \text{H}_2\text{CO}_3 < \text{CH}_3\text{COOH} < \text{HF}
Practice Ionic Equilibrium on Quantrex Academy →

More from Ionic Equilibrium

What amount of NaOH should be dissolved in a 500 mL solution, so that the p^H of solution… MHT CET Medical 2026Which of the following buffer solutions is used for precipitation of cations of the III A… MHT CET Medical 2026The degree of dissociation of weak acid is directly proportional to MHT CET Medical 2026Which from the following is Lewis base? MHT CET Medical 2026The solubility of Fe(OH)_3 is x mole per liter. Find its K_ sp . MHT CET Medical 2026The Basic buffer solution is made with 0.1\ M\ NH_4OH and 0.2\ M\ NH_4Cl . If K_b for the… MHT CET Medical 2026The hydrogen ion concentration of the ocean is about 2 × 10^ -9 \ M . What is the pOH of… MHT CET Medical 2026Calculate the dissociation constant of a weak monobasic acid if it is 0.04% dissociated… MHT CET Medical 2026 Full Ionic Equilibrium list All MHT CET Medical PYQs