Question

10.0 mL of 0.05 M KMnO₄ solution was consumed in a titration with 10.0 mL of given oxalic acid dihydrate solution. The strength of given oxalic acid solution is ........ x 10^–2 g/L. (Round off to the nearest integer)

Answer 1

n_eq KMnO₄ = n_eq H₂C₂O₄ . 2H₂O

or, \(\frac{10\times0.05}{1000}\times5\) = \(\frac{10\times M}{1000}\times2\)

Conc. of oxalic acid solution = 0.125 M 

= 0.125 × 126 g /L = 15.75 g/L 

= 1575 x 10^–2 g/L

Comments

Why multiplied by × 126 g /L ??

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Because in the question it is oxalic acid "dihydrate"  i.e. its total molecular weight will be 126 not 90