[Borek]

What units is your concetration expressed in?

0.07mole in 300ml
V/1000 x M = mole = 300/1000 x M = 0.07
M = 0.07 x 1000/300 = 0.233
so pH = -log 0.233 = 0.632
correct?

Result is correct, but you did everything possible to evade my question - most of your calculations don't have any units, and if the do have units - they are either wrong or it is not possible to tell if they are OK. So, your result is numerically correct, but you have no idea why and the next time you will be asked to do similar question you will be completely helpless.

[AWK]

Use only one decimal point for pH because the error of your calculations do not take into account the influence of ionic strength. The real value of pH (that you can measure) will be close to 0.75.