JEE Main & Advanced Sample Paper JEE Main Sample Paper-45

  • question_answer
    Analysis shows that nickel oxide has the formula \[N{{i}_{0.98}}O\]. What fraction of the nickel exists\[N{{i}^{3+}}\] ions?

    A)  1%                             

    B)  2%            

    C)  4%                             

    D)  8%

    Correct Answer: C

    Solution :

     \[\because \] \[N{{i}_{98}}{{O}_{100}}\] means total charge due to oxygen atoms \[=-2\times 100=-200\] \[\therefore \] Total charge due to Ni ions must be +200. Let \[N{{i}^{2+}}\] ions be \[x\]. \[\therefore \]    \[N{{i}^{3+}}\] ions will be \[(98-x)\] \[\therefore \]    \[(+2)\,(x)+\,(+3)\,(98-x)=+200\] \[\therefore \]    \[x=94\] \[\therefore \] Fraction of Ni as \[N{{i}^{2+}}=\frac{94}{98}\times 100=96%\] And fraction of Ni as \[N{{i}^{3+}}=\frac{4}{98}\times 100=4%\]

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