pH question finding the change

i have tried to solve these questions but I still was not able to obtain the right answer. Where have I gone wrong ?
Thanks.

(edited 7 years ago)

1477693996516-1834346926.jpg516.8KB

Reply 1

coconut64

here is a better picture .

Reply 2

charco

Study Forum Helper

Original post by coconut64

here is a better picture .

question 6 you have written the initial [HCl] wrongly...

OK I see what you have done.

You are calculating pH from the number of moles NOT from the concentration.

pH = -log[H+]

(edited 7 years ago)

Reply 3

coconut64

Original post by charco

question 6 you have written the initial [HCl] wrongly...

OK I see what you have done.

You are calculating pH from the number of moles NOT from the concentration.

pH = -log[H+]

Appreciate your help. I think I managed to get it at the end. it is such a silly mistake and I will make sure I do proper working next time.

Reply 4

coconut64

Original post by charco

question 6 you have written the initial [HCl] wrongly...

OK I see what you have done.

You are calculating pH from the number of moles NOT from the concentration.

pH = -log[H+]

For question7, I obtained 11.3 ( 13.176-1.903) for the pH change. However the answer is 11.58. Have I got it wrong?