2. Solved Papers
  3. AFMC

AFMC AFMC Solved Paper-2008

  • question_answer
    The formula mass of Mohr?s salt is 392. The iron present in it is oxidised by \[\text{KMn}{{\text{O}}_{\text{4}}}\]in acid medium. The equivalent mass of Mohr? s salt is

    A)  392                                       

    B)  31.6

    C)  278                                       

    D)  156

    Correct Answer: A

    Solution :

                     Mohr's salt is \[{{(N{{H}_{4}})}_{2}}S{{O}_{4}}.FeS{{O}_{4}}.6{{H}_{2}}O.\] The equation is : \[5F{{e}^{2+}}MnO_{4}^{-}+8{{H}^{+}}\xrightarrow[{}]{{}}\]\[5F{{e}^{3+}}+M{{n}^{2+}}+4{{H}_{2}}O\] Total change in oxidation number of iron \[=(+3)-(+2)\] \[=+1\] So, equivalent wt. of Mohr's salt \[\text{=}\frac{\text{Mol}\text{. wt}\text{. of Mohr }\!\!'\!\!\text{ s salt}}{\text{1}}\] \[=\frac{392}{1}\] = 392


You need to login to perform this action.
You will be redirected in 3 sec spinner