An aqueous buffer is prepared by adding 100 mL of 0.1 mol L -1 acetic acid to 50 mL of 0.2 mol L -1 of sodium acetate. If p K a of acetic acid is 4.76, the pH of the buffer is

Question

An aqueous buffer is prepared by adding 100 mL of 0.1 mol L -1 acetic acid to 50 mL of 0.2 mol L -1 of sodium acetate. If p K a of acetic acid is 4.76, the pH of the buffer is (A) 4.26 (B) 5.76 (C) 3.76 (D) 4.76

Tardigrade Admin · Accepted Answer

M text eq of CH 3 COOH =100 × 0.1=10 M text eq of CH 3 COONa =50 × 0.2=10 According to Henderson equation pH = p Ka+ log ([ text salt ]/[ text acid ]) pH = p Ka+( log [ CH 3 COO -]/ log [ CH 3 COOH ]) pH =4.76+ log (10/10) pH =4.76+ log 1 ⇒ pH =4.76

Q. An aqueous buffer is prepared by adding 100mL of 0.1molL−1 acetic acid to 50mL of 0.2molL−1 of sodium acetate. If pKa​ of acetic acid is 4.76, the pH of the buffer is

4.26

5.76

3.76

4.76

Meq ​ of CH3​COOH=100×0.1=10 Meq ​ of CH3​COONa=50×0.2=10 According to Henderson equation pH=pKa​+log[ acid ][ salt]​ pH=pKa​+log[CH3​COOH]log[CH3​COO−]​ pH=4.76+log1010​ pH=4.76+log1 ⇒pH=4.76

Q. An aqueous buffer is prepared by adding $100 m L$ of $0.1 m o l L^{- 1}$ acetic acid to $50 m L$ of $0.2 m o l L^{- 1}$ of sodium acetate. If $p K_{a}$ of acetic acid is $4.76$ , the $p H$ of the buffer is