`20 cm^(3)` of a solution of oxalic acid requires `25 cm^(3)` of 0.2 N potassium permanganate to react completely (a) Calculate the normality of oxalic acid solutions. (b) What volume of this oxalic acid solution when made upto `250 cm^(3)` gives 0.2 N solution?

Explanation

(a) `underset("oxidising agent")(N_(1)V_(1)) = underset("reducing agent")(N_(2)V_(2)) rArr N_(2) = (N_(1)V_(1))/(V_(2)) = (25 xx 0.2)/20 = 0.25`
Normality of oxalic acid solutions = 0.25
(b) `underset("dilute solution")(N_(1)V_(1)) = underset("strong solution of oxalic acid") (N_(2)V_(2)) rArr N_(2) = (N_(1)V_(1))/V_(2) = (250 xx 0.2)/(0.25) = 200`.
Normality of oxalic acid solution = 200. Volume of oxalic acid solution required = `200 cm^(3)`.