Question

How many moles of acidified $ FeS{{O}_{4}} $ can be completely oxidised by one mole of $ KMn{{O}_{4}} $ ?

• A. 10
• B. 5
• C. 6
• D. 2

Answer 1

Answer: (B)

The balanced equation of acidified
$ FeS{{O}_{4}} $ with $ KMn{{O}_{4}} $ is $ 2KMn{{O}_{4}}+8{{H}_{2}}S{{O}_{4}}\underset{ferrous\text{ }sulphate}{\mathop{+10FeS{{O}_{4}}}}\,\xrightarrow{{}} $
$ {{K}_{2}}S{{O}_{4}}+2MnS{{O}_{4}}\underset{ferric\text{ }sulphate}{\mathop{+5F{{e}_{2}}{{(S{{O}_{4}})}_{3}}+}}\,8{{H}_{2}}O $
$ \because $ 2 mole of KMn04 oxidised = 10 moles of $ FeS{{O}_{4}} $ $ \therefore $ 1 mole of KMn04 will oxidise $ =\frac{10}{2}=5 $ moles of $ FeS{{O}_{4}} $