A 25.0ml sample of 0.1 M HCl is titrated with 0.1 M NaOH . What is the pH of the solution at the points where 24.9 and 25.1 ml of NaOH have been added ?

Options

A. `3.70,10.70 `
B. ` 3.30, 10.30`
C. ` 3. 70 , 10 .30`
D. ` 3. 0, 11 . 10 `

Answer

C

Explanation

` at =24.9 ml`
` N_aV_a =25xx 0.1 , N_b V_b =24.9 xx 0.1`
` [H^(+) ]_("left") =(2.5 - 2.49)/( 50.1 ) =2 xx 10 ^(_4)`
` pOH =3.7 rArr pH =10.3`