pH value of which one of the following is NOT equal to one ?

Options

A. `0.1" M HNO"_(3)`
B. `0.05" M "H_(2)SO_(4)`
C. `0.1" M "CH_(3)COOH`
D. `50" cm"^(3)` of 0.4 M HCl + 50 `"cm"^(3)` of `0.2" M NaOH"`

Answer

C

Explanation

`pH=-log[H^(+)]`
(a) Value of `pH=0.1" M HNO"_(3)=-log[0.1]=1`
(b) Value of `pH=0.05H_(2)SO_(4)=-log[2xx0.05]=1`
(c) Value of `pH=0.1"M "CH_(3)COOH!=1` as it is a weak acid so, will not undergo complete ionization.
(d) Milli - equivalent of acid `=50xx0.4=20`
Milli-equivalent of base `=50xx0.2=10`
Remaining acid `=20-10=10` milli-eq.
`[H^(+)]=(10)/(50+50)=(10)/(100)=0.1`
`pH=-log[H^(+)]=1`.