Ammonium acetate which is 0.01 M , is hydrolysed to 0.001 M concentration . Calculate the change in pH in 0.001 M solution , if initially pH = `pK_(a)`

Options

A. 5
B. 10
C. 100
D. 1

Answer

D

Explanation

`underset(0.01M)(CH_(3)COONH_(4)) + H_(2)O to underset(0.001 M)(CH_(3)COOH) + NH_(4) OH`
`pH = pK_(a) + log ""([CH_(3)COONH_(4)])/([CH_(3)COOH])`
`pK_(a) + log[(0.1)/(0.001)]`
`= pK_(a) + log 10`
= `pK_(a) + 1`
`therefore` Change in pH = 1