JEE Advanced levelSingle correct optionDifficulty 3 of 3eq089
10.0mL of hydrogen peroxide is diluted to 100mL. A 20.0mL portion is treated with excess KI and acid (HX2OX2+2IX−+2HX+IX2+2HX2O), and the iodine needs 15.2mL of 0.100M thiosulphate. Taking 1 mol of HX2OX2 to give 11.2 L of OX2 at STP on decomposition, the volume strength of the original solution is
A8.51 V
B4.26 V
C0.85 V
D2.13 V
Answer: B
I2 in 20.0 mL = (0.0152 x 0.100)/2 = 7.60e-04 mol = mol H2O2. In 100 mL: 3.80e-03 mol, which was in 10.0 mL, so M = 0.380. Volume strength = M x 11.2 = 4.26 V.