JEE Main & Advanced JEE Main Paper (Held On 15 April 2018) Slot-I

  • question_answer
    When an electric current is passes through acidified water, 112mL of hydrogen gas at N.T.P. was collected at the cathode in 965 seconds. The current passed, in ampere, is _______. [JEE Online 15-04-2018]

    A) 0.1                              

    B) 2.0      

    C) 1.0                              

    D) 0.5      

    Correct Answer: C

    Solution :

    Reduction at cathode:\[2{{H}^{+}}(aq)+2{{e}^{-}}\to {{H}_{2}}(g)\] At N.T.P, 22.4 L (or 22400 mL) of \[{{H}_{2}}=1\] mole of \[{{H}_{2}}\] 112 mL of \[{{H}_{2}}=\frac{112}{22400}\times 1=0.005\] mole of \[{{H}_{2}}\] Moles of \[{{H}_{2}}\]produced \[=\frac{I(A)\times t(s)}{96500(C/mol{{e}^{-}})}\times \] mole ratio 0.005mol\[=\frac{I(A)\times 965s}{96500(C/mol{{e}^{-}})}\times \frac{1\,\,mol\,\,{{H}_{2}}}{2\,\,mol\,\,{{e}^{-}}}\] \[I=1A\]


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