Which of the following solutions will have pH close to 1.0 ?

Options

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

Answer

D

Explanation

` "In " (d) M_(H^(+)) =(M_(1)V_(1)- M_(2)V_(2))/(V_(1)+V_(2)) `
`=(0.1 xx 75 -0.2xx 25)/(100) = (7.5 -5.0)/(100)`
`M_(H^(+)) =(2.5)/(100) =2.5 xx 10^(-2) M = 25 xx 10^(-3) M`
`pH =- log [H^(+)] =- log (25xx10^(-3))`
`=- 1.398 +3 = 1.602`
In this case pH is close to 1.