# Working out the ph of CH3COONa

Hi ppl. I have a question. I'm given the pka of ethanoic acid/ethanoate ions at 4.75 and i have to work out the ph of a 5*10^-2 moldm3 solution of sodium ethanoate. I worked it out by getting the Ka from 10^-4.75 and then saying that the concentration of Ch3COO- in the dissociation of ethanoic acid is also 5*10^-2 moldm3. Then i used the equation for the Ka to get the corresponding concentration of H+ ions in this dissociation and hence the ph, is this method of reasoning correct? Thanks, Joe