How many grams of glyoxylic acid and sodium glyoxylate are needed to prepare 1.25 l of a 1.90 m buffer at pll 3.357 the pk, of glyoxylic acid is 3.34. note: use the monohydrate forms, hcoco, h. h,0 and hcoco, na · h, o glyoxylic acid needed: g hcoco, h. h,o sodium glyoxylate needed: g hcoco, na - h,