`4.9 g` of `K_(2)Cr_(2)O_(7)` is taken to prepare `0.1 L` of the solutio. `10 mL` of this solution is further taken to oxidise `Sn^(2+)` ion into `Sn^(4+) ion` so produced is used in second reaction to prepare `Fe^(3+)` ion then the millimoles of `Fe^(3+)` ion formed will be (assume all other components are in sufficient amount)[Molar mass of `K_(2)Cr_(2)O_(7)=294 g`].

Options

A. `5`
B. `20`
C. `10`
D. none of these

Answer

C

Explanation

`K_(2)Cr_(2)O_(7)+Sn^(2+) rarr Sn^(4+)+Cr^(3+)`