How many moles of `K_(2)Cr_(2) O_(7)` are reduced by 1 mole of formic acid -

Options

A. `1//3`
B. `1//6`
C. `2//3`
D. 1

Answer

A

Explanation

`Cr_(2)O_(7)^(2-)+14H^(+)+6e^(-)rarr2Cr^(3+)+7H_2O`
`{:((Sn^(2+)rarrSn^(4+)+2e^(-))xx3),(bar(Cr_(2)O_(7)^(2-)+14H^(+)+3Sn^(2+)rarr3Sn^(4+)+2Cr^(3+)+7H_2O)):}`
It is clear from this equation that 3 moles of `Sn^(2+)` reduce one mole of `Cr_(2)O_(7)^(2-) ` hence 1 mol. of `Sn^(2+)` will reduce `1/3` moles of `Cr_(2)O_7^(2-)`