PH calculation question?

Question

If you add 1.0 ml of 1.0 M acetic acid to 1 L water, what would the pH become?

Thanks

Answer 1

it would still be about 7. Acetic acid is very weak, and the ratio 1:1000 means its effect will be minute

Answer 2

Moles acetic acid = 0.001 L x 1.0 M = 0.001

total volume = 1L + 0.001 = 1.001 L

concentration acetic acid = 0.001 / 1.001 =0.0010 M

CH3COOH <-----> CH3COO- + H+

1.8 x 10^-5 = x^2 / 0.0010-x

x = [H+] = 0.00013 M

pH = - log 0.00013 = 3.9