Hydrogen peroxide solution (20 mL ) reacts quantitatively with a solution of KMnO 4(20 mL ) acidified with dilute H 2 SO 4. The same volume of the KMnO 4 solution is just decolourised by 10 mL of MnSO 4 in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO 2. The brown precipitate is dissolved in 10 mL of 0.2 M sodium oxalate under boiling condition in the presence of dilute H 2 SO 4. calculate the molarity of H 2 O 2. Round off your answer to nearest integer after multiplying with 100 .

Question

Hydrogen peroxide solution (20 mL ) reacts quantitatively with a solution of KMnO 4(20 mL ) acidified with dilute H 2 SO 4. The same volume of the KMnO 4 solution is just decolourised by 10 mL of MnSO 4 in neutral medium simultaneously forming a dark brown precipitate of hydrated MnO 2. The brown precipitate is dissolved in 10 mL of 0.2 M sodium oxalate under boiling condition in the presence of dilute H 2 SO 4. calculate the molarity of H 2 O 2. Round off your answer to nearest integer after multiplying with 100 . (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

I 2 KMnO 4+3 H 2 SO 4+5 H 2 O 2 arrow K 2 SO 4+2 MnSO 4+8 H 2 O +5 O 2 II 2 KMnO 4+3 MnSO 4+2 H 2 O arrow 5 MnO 2+ K 2 SO 4+2 H 2 SO 4 III MnO 2+ Na 2 C 2 O 4+2 H 2 SO 4 arrow MnSO 4+ Na 2 SO 4+2 CO 2+ H 2 O Reaction (III) ⇒ mM of Na 2 C 2 O 4=10 mL × 0.2 M =2 mM = mM of MnO 2 Reaction (II) ⇒ mM of KMnO 4=2 × (2/5)=(4/5) mM Reaction (I) ⇒ mM of H 2 O 2=(4/5) × (5/2)=2 mM 2 mM 2 of H 2 O 2=20 mL × M H 2 O 2 M H 2 O 2=0.1 M