When 10 mL of an aqueous solution of KMnO 4 was titrated in acidic medium, equal volume of 0.1 M of an aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of KMnO 4 in grams per litre is × 10-2 . (Nearest integer) [ Atomic mass of K =39, Mn =55, O =16]

Question

When 10 mL of an aqueous solution of KMnO 4 was titrated in acidic medium, equal volume of 0.1 M of an aqueous solution of ferrous sulphate was required for complete discharge of colour. The strength of KMnO 4 in grams per litre is × 10-2 . (Nearest integer) [ Atomic mass of K =39, Mn =55, O =16] (A)  (B)  (C)  (D)

Tardigrade Admin · Accepted Answer

Let molarity of KMnO 4= x KMnO 4+ FeSO 4 arrow Fe 2( SO 4)3+ Mn 2+ n =5 n =1 (Equivalents of KMnO 4 reacted) = (Equivalents of FeSO 4 reacted) ⇒ (5 × x × 10 ml )=1 × 0.1 × 10 ml ⇒ x =0.02 M Molar mass of KMnO 4=158 gm / mol ⇒ Strength =( x × 158)=3.16 g / ℓ

Let molarity of KMnO4​=x KMnO4​+FeSO4​→Fe2​(SO4​)3​+Mn2+ n=5n=1 (Equivalents of KMnO4​ reacted) = (Equivalents of FeSO4​ reacted) ⇒(5×x×10ml)=1×0.1×10ml ⇒x=0.02M Molar mass of KMnO4​=158gm/mol ⇒ Strength =(x×158)=3.16g/ℓ