H3PO4 is an acid and one of its salt is NaH2PO4. What  volume  of 1M NaOH  solution should be added to 12g of NaH2PO4  to convert it intoNa3PO4 ?

The reaction involved is NaH2PO4+2NaOH→Na3PO4+2H2OFrom the reaction, 1 mol NaH2PO4+2H2O,reacts with 2 mol  NaOH Number of moles of NaH2PO4=12120=0.1molTherefore, number moles of NaOH =2×0.1=0.2 molUsing the molarity of NaOH we get the final answer.