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JEE Main & Advanced Sample Paper JEE Main Sample Paper-16

  • question_answer
    1 mol Fe reacts completely with 0.7 mol of \[{{O}_{2}}\] to give a mixture of only \[FeO\And F{{e}_{2}}{{O}_{3}}.\] The mol ratio of \[F{{e}^{+3}}\] to\[F{{e}^{+2}}\] in product mixture is:

    A)  1 : 2                                      

    B)  2 : 1

    C)  2 : 3                                      

    D)  4 : 1

    Correct Answer: D

    Solution :

    \[Fe\]+ \[{{O}_{2}}\]\[\xrightarrow[{}]{{}}\] \[FeO\]\[+\] \[F{{e}_{2}}{{O}_{3}}\]
    1 0.7 0 0
    0 0 A b
    Let moles of \[FeO=a.\]                \[F{{e}_{2}}{{O}_{3}}=b\] Applying POAC, \[a+2b=1\]                            ?(1)                                 \[a+3b=0.7\times 2\]                    .(2) Solving (1) & (2), \[a=0.,b=0.4\] moles of \[F{{e}^{3+}}=2b=0.8\] moles of \[F{{e}^{2+}}=a=0.2\] \[\therefore \]\[\frac{{{n}_{F{{e}^{3+}}}}}{{{n}_{F{{e}^{2+}}}}}=\frac{0.8}{0.2}=\frac{4}{1}\]


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