JIPMER Jipmer Medical Solved Paper-2010

  • question_answer
    How Jong it will take to deposit 1.0 g of chromium when a current of 1.25 A flows through a solution of chromium (III) sulphate? (Molar mass of Cr = 52)

    A)  1.24 min             

    B)  124 h                   

    C)  1.24 s                                   

    D)  none of these

    Correct Answer: B

    Solution :

    \[C{{r}^{3+}}+3{{e}^{-}}\xrightarrow{{}}Cr(s)\] 3 mol or 3 x 96500 C of electricity are needed to deposit 1 mol or 52 g of Cr. 52 g of Cr require current \[=3\times 96500\,C\] 1 g of Cr will require current                 \[=\frac{3\times 96500}{52}C\] \[=5567.3\,C\] Now, number of coulombs = current (ampere) x t (seconds) \[\therefore \,\,\text{Time}\,\text{(s)}\,\text{required}\,\text{=}\,\frac{\text{no}\text{. of coulombs}}{\text{current }\left( \text{ampere} \right)}\] \[=\frac{5567.3\,C}{1.25\,A}\] \[=4453.8\,\,s\] or                            \[=1.24\,h\]


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