NEET Sample Paper NEET Sample Test Paper-2

  • question_answer
    What is the standard free energy change at \[{{25}^{o}}C\] for the reaction
    \[C{{d}_{(s)}}+P{{b}^{2+}}_{(aq)}\xrightarrow{{}}C{{d}^{2+}}_{(aq)}+P{{b}_{(s)}}\]
    Given \[E_{{\scriptstyle{}^{C{{d}^{2+}}}/{}_{Cd}}}^{o}=-0.403\,V\]
    \[E_{{\scriptstyle{}^{P{{b}^{2+}}}/{}_{Pb}}}^{o}=-0.125\,V\]

    A)  \[-5.346\text{ }kJ\]

    B)  \[53.46\text{ }kJ\]

    C)  \[-10.69\text{ }kJ\]         

    D)  \[-106.92\text{ }kJ\]

    Correct Answer: B

    Solution :

    \[C{{d}_{(g)}}+P{{b}^{2+}}_{(aq)}\xrightarrow{{}}C{{d}^{2+}}_{(aq)}+P{{b}_{(s)}}\] \[n=2\] \[\Delta G=nFE\] \[=-2\times 96500\times E_{cell}^{o}\] \[=-2\times 96500\times ({{E}^{o}}_{cathode}-{{E}^{o}}_{anode})\] \[=-2\times 96500\,(-0.126+0.403)\] \[=-53461J=-53.46\,kJ\]


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