One third litre of `x MK_(2)Cr_(2)O_(7)` is required to completely oxidise 2L of 0.1 M ferrous ammonium sulphate in acid medium. What is `x` ?

Options

A. 0.03
B. 0.1
C. 0.2
D. 0.5

Answer

B

Explanation

`x MK_(2)Cr_(2)O_(7)+6FeSO_(4)+7H_(2)SO_(4)rarr7H_(2)O+Cr_(2)(SO_(4))_(3)+3Fe_(2)(SO_(4))_(3)+K_(2)SO_(4)`
`FeSO_(4).(NH_(4))_(2)SO_(4).6H_(2)O` is Mohr salt (0.1 M)
Given, `V_(1)` (volume of `K_(2)Cr_(2)O_(7)`)`=1/3 L`
Here, `K_(2)Cr_(2)O_(7)` is required to completely oxidise ferrous ammonium sulphate (0.1 M). Therefore, molarity of `K_(2)Cr_(2)O_(7)=0.1M`
Thus, option (b) is correct.