100 ml of 0.1N FeSO₄ solution will be completely oxidised by ‘x’ gms of K₂Cr₂O₇ in acidic medium (Mol.wt = 294). The value of ‘x’ is

FeSO₄                       K₂Cr₂O₇ $\left({\mathrm{Cr}}_2{\mathrm{O}}_7^{-2}\to {\mathrm{Cr}}^{+3}\right)$

V₁=100 ml              n-factor = 6  

N₁ = 0.1N, GEW of K₂Cr₂O₇ in acidic medium = $\frac{294}{6}=49\mathrm{g}$

At neutralisation point (or) equivalent point,

 $\frac{{\mathrm{V}}_1{\mathrm{N}}_1}{1000}=\frac{{\mathrm{W}}_{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}}{\mathrm{GEW} \mathrm{of} {\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}$

$\frac{{\mathrm{V}}_1{\mathrm{N}}_1}{1000}=\frac{{\mathrm{W}}_{{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}}{\mathrm{GEW}\text{ of }{\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7}$

$\frac{100(0.1)}{1000}=\frac{\mathrm{x}}{49}$

   x = 0.49g

Wt. of K₂Cr₂O₇ required = 0.49g