NEET Chemistry NEET PYQ-The d-and f-Block Elements

  • question_answer
    The number of moles of KMnO4 that will be needed to react with one mole of sulphite ion in acidic solution is:        [AIPMT (S) 2007]

    A) \[\frac{3}{5}\]

    B) \[\frac{4}{5}\]

    C) \[\frac{2}{5}\]

    D) 1

    Correct Answer: C

    Solution :

    [c] \[2KMn{{O}_{4}}+3{{H}_{2}}S{{O}_{4}}\xrightarrow{{}}\]
                            \[{{K}_{2}}S{{O}_{4}}+2MnS{{O}_{4}}+3{{H}_{2}}O+5[O]\]
                \[[MnO_{4}^{-}+8{{H}^{+}}+5{{e}^{-}}\xrightarrow{{}}M{{n}^{2+}}+4{{H}_{2}}O]\times 2\]
                \[\underline{(SO_{3}^{2-}+{{H}_{2}}O\xrightarrow{{}}SO_{4}^{2-}+2{{H}^{+}}+2{{e}^{-}})\times 5}\]
                \[\begin{align}   & 2MnO_{4}^{-}+6{{H}^{+}}+5SO_{3}^{2-}\xrightarrow[{}]{{}} \\  & 2M{{n}^{2+}}+SO_{4}^{2-}+3{{H}_{2}}O \\ \end{align}\]
                5 moles of sulphite ion react with = 2 moles of
                \[MnO_{4}^{-}\]
                So, 1 mole of sulphite ion react with = \[\frac{2}{5}\]moles of \[MnO_{4}^{-}\].


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