11. What mass of sodium benzoate should be added to 160.0mL of a 0.17M benzoic acid solution in order to obtain a buffer with a pH of 4.30?
3 answers
I don't think we have any experts in the school subject of NCCU.
millimols benzoic acid = mL x M = about 27 but that's an estimate and you should redo the math.
Then pH = pKa + log (base)/(acid)
4.30 = pKa benzoic acid + log benzoate/27
Look up the value of pKa for benzoic acid, substitute, solve for base. That will be millimols sodium benzoate needed. Change to mols, then mols = g/molar mass. You know molar mass and mols, solve for grams.
Then pH = pKa + log (base)/(acid)
4.30 = pKa benzoic acid + log benzoate/27
Look up the value of pKa for benzoic acid, substitute, solve for base. That will be millimols sodium benzoate needed. Change to mols, then mols = g/molar mass. You know molar mass and mols, solve for grams.
I would have answered this much quicker if you had typed in the subject instead of something obscure like NCCU.