AIIMS AIIMS Solved Paper-2011

  • question_answer
    How many atoms of calcium will be deposited from a solution of \[CaC{{l}_{2}}\] by a current of 5 mA flowing for 60 s?

    A)  \[4.68\times {{10}^{18}}\]     

    B)         \[4.68\times {{10}^{15}}\]          

    C)         \[4.68\times {{10}^{12}}\]     

    D)         \[4.68\times {{10}^{9}}\]

    Correct Answer: A

    Solution :

    Given, \[~i=25mA=0.0025\text{ }A\] \[t=\,\,60s\] \[Q=it\] \[=0.0025\times 60\] \[=1.5C\] number of electrons in 1.5 C \[=\frac{Q\times Avogadro\,number}{96500}\] \[=\frac{1.5\times 6.023\times {{10}^{23}}}{96500}\] \[=9.36\times {{10}^{18}}\] \[Ca\xrightarrow{{}}C{{a}^{2+}}+2{{e}^{-}}\] \[2{{e}^{-}}\] are required to deposit 1 Ca atom. \[\therefore \] number of Ca atoms deposited \[=\frac{no.\,of\,electrons}{2}\] \[=\frac{9.36\times {{10}^{18}}}{2}\] \[=4.68\times {{10}^{18}}\]


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