Haryana PMT Haryana PMT Solved Paper-2008

  • question_answer
    How many atoms of calcium will be deposited from a solution of \[CaC{{l}_{2}}\]by a current of 25 milliamperes 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 :

                    Charge \[q=i\times t=\frac{25}{1000}\times 60=1.5C\] \[\underset{2\times 96500C}{\mathop{C{{a}^{2+}}}}\,+2{{e}^{-}}\xrightarrow{{}}\underset{6.02\times {{10}^{23}}}{\mathop{Ca}}\,\] \[\because \] At \[2\times 96500\text{ }C,\] the deposited \[Ca\] atoms                 \[=6.02\times {{10}^{23}}\] \[\therefore \] At\[1.5C\], the deposite \[Ca\] atoms                 \[=\frac{6.02\times {{10}^{23}}\times 1.5}{2\times 96500}\]                 \[=4.68\times {{10}^{18}}\]


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