Electrochemistry 1 Question 45
44. In a fuel cell hydrogen and oxygen react to produces electricity. In the process hydrogen gas is oxidised at the anode and oxygen at the cathode. If $67.2 \mathrm{~L}$ of $\mathrm{H}_{2}$ at STP react in $15 \mathrm{~min}$, what is the average current produced? If the entire current is used for electro deposition of copper from copper (II) solution, how many grams of copper will be deposited?
Anode reaction : $\quad \mathrm{H}{2}+2 \mathrm{OH}^{-} \longrightarrow 2 \mathrm{H}{2} \mathrm{O}+2 e^{-}$
Cathode reaction : $\mathrm{O}{2}+2 \mathrm{H}{2} \mathrm{O}+2 e^{-} \longrightarrow 4 \mathrm{OH}^{-}(1988,4 \mathrm{M})$
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Answer:
Correct Answer: 44. $(190.50$
Solution:
- Total number of gram equivalent of $\mathrm{H}_{2}$ used $=\frac{67.2}{11.2}=6$
$\Rightarrow \quad 6 \times 96500=15 \times 60 \times I \Rightarrow I=643.33 \mathrm{~A}$
Mass of $\mathrm{Cu}$ deposited $=6 \times \frac{63.5}{2} \mathrm{~g}=190.50 \mathrm{~g}$
