The pKa of acetic acid and pKb of NH4OH are 4.76 and 4.75, respectively. Calculate the pH of ammonium acetate solution.

Question

The pKa of acetic acid and pKb of NH4OH are 4.76 and 4.75, respectively. Calculate the pH of ammonium acetate solution. (A) 7.5 (B) 7.005 (C) 7.05 (D) 7.55

Tardigrade Admin · Accepted Answer

Acetic acid and NH4OH are weak acid (.WA.) and weak base (.WB.) respectively. When they combine a salt of WA and WB i.e., ammonium acetate is formed. So by using hydrolysis equation for salts of WA and WB , pH=(1/2)(.pKw+pKa-pKb.) = (1/2) (14 + 4.76 - 4.75) =7+0.005=7.005 .

Q. The pKa​ of acetic acid and pKb​ of NH4​OH are 4.76 and 4.75, respectively. Calculate the pH of ammonium acetate solution.

7.5

7.005

7.05

7.55

Acetic acid and NH4​OH are weak acid (WA​) and weak base (WB​) respectively. When they combine a salt of WA​ and WB​ i.e., ammonium acetate is formed. So by using hydrolysis equation for salts of WA​ and WB​ , pH=21​(pKw​+pKa​−pKb​) =21​(14+4.76−4.75) =7+0.005=7.005 .

Q. The $p K_{a}$ of acetic acid and $p K_{b}$ of $N H_{4} O H$ are 4.76 and 4.75, respectively. Calculate the pH of ammonium acetate solution.