JEE Main 16 March 2021 Shift 2 Solved Paper

H3PO3

50‌ml 1M

+

2NaOH

1M V=?

⟶Na2HPO3+2H2O
Millimoles of H3PO3=M×V=1×50=50
For 1 millimole of H3PO3, we require 2 millimoles of NaOH.
For 50 millimole of H3PO3, we require (2×50)=100 millimoles of NaOH.
Millimoles of NaOH=M×V=100
1×V‌‌=100
V‌‌=100mL

H3PO2

100‌mL 2M

+

NaOH

1M V=?

→NaH2PO2+H2O
Millimoles of H3PO2=M×V=2×100=200
For 1 millimole of H3PO2, we require 1 millimoles of NaOH.
For 200 millimole of H3PO2, we require 200 millimoles of NaOH.
So, volume of NaOH=200mL