30g of the palm shell were mixed with 15ml H3PO4 and 100ml of distilled water in a 250ml conical flask.The concentration of H3PO4 solution was 2.2M, from question,how to prepare those from ortho phosporic acid (98g/mol).Do help me, is it need to make a stock solution first and take from stock 15ml and mix with 100ml of distilled water?

I don't understand the question.