Question

How do I convert 0.67275 M of acetic acid solution to V/V %?

Answer 1

Do you have a density?

0.67275 M = 0.67275 moles acetic acid/L soln.
That is 0.67275 moles x molar mass acetic acid = grams acetic acid = ??
mass = volume x density; convert g acetic acid to volume acetic acid.
And that is mL acetic acid/1000 mL soln. Convert that to mL acetic acid/100 mL soln. That should do it.