500 mL of 0.2 M aqueous solution of acetic acid is mixed with 500 mL of 0.2 M HCl at 250° C. (i) Calculate the degree of dissociation of acetic acid in the resulting solution and pH of the solution. (ii) If 6 g of NaOH is added to the above solution, determine the final pH (assuming there is no change in volume on mixing, Ka of acetic acid is 1.75 × 10-1 mol / L).

Question

500 mL of 0.2 M aqueous solution of acetic acid is mixed with 500 mL of 0.2 M HCl at 250° C. (i) Calculate the degree of dissociation of acetic acid in the resulting solution and pH of the solution. (ii) If 6 g of NaOH is added to the above solution, determine the final pH (assuming there is no change in volume on mixing, Ka of acetic acid is 1.75 × 10-1 mol / L). (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/chemistry/a76f16c2f017a00211d347e7d635f527-.png" /> If no HCl is present, [ HCl ]=(0.2/2)=0.10 M [ CH 3 COOH ]=0.10 M The major contributor of H +in solution is HI Ka=(C α(0.1)/C(1-α))=1.75 × 10-5 α=1.75 × 10-4 (ii) m mol of NaOH added =(6/40) × 1000=150 m mol of HCl =500 × 0.2=100 m mol of CH 3 COOH =500 × 0.2=100 After neutralisation, mmol of CH 3 COOH =50 mmol of CH 3 COONa =50 pH = p Ka=4.75