JEE Main & Advanced Chemistry Electrochemistry / विद्युत् रसायन Question Bank Topic Test - Electrochemistry

  • question_answer
    A current of 0.250 A is passed through 400 mL of a 2, 0 M solution of NaCl for 35 minutes. What will be the pH of the solution after the current is turned off?

    A) 12.98 

    B) 12.13    

    C) 10.48

    D) 9.24

    Correct Answer: B

    Solution :

    [b] After electrolysis aqueous NaCl is converted into aqueous NaOH. The quantity of electricity passed
    \[=\frac{0.250\times 35\times 60}{96500C}A\,s=5.44\times {{10}^{-3}}F\]
    The number of equivalents of \[O{{H}^{-}}\] ion formed
    \[=5.44\times {{10}^{-3}}\]
    \[\therefore \]      Molarity of \[NaOH=\frac{5.44\times {{10}^{-3}}}{0.400L}eq.\]
    \[=1.36\times {{10}^{-2}}\]
    \[pOH=-\log (1.36\times {{10}^{-2}})=2.00-0.13=1.87\]
    \[\therefore \]      \[pH=12.13\]


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