Which of the following mixture solution has `pH ~~ 1.0` ?

Options

A. 100 ml of `(M)/(10)HCl +100` ml of `(M)/(10)` NaOH
B. 55 ml of `(M)/(10)HCl+45` ml of `(M)/(10)` NaOH
C. 10 ml of `(M)/(10)HCl+90` ml of `(M)/(10)` NaOH
D. 75 ml of `(M)/(5)HCl+25` ml of `(M)/(5)` NaOH.

Answer

D

Explanation

25 ml of M/5 NaOH will neutralize 25 ml of M/5 HCl. The remaining 50 ml of M/5 will be equal to 100 ml of M/10 HCl.
`pH=-log[H^(+)]`
`=-log 10^(-1)=1`