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Calculate the time required to liberate 9g of Aluminium metal, when a current of 18A...

Chemistry
JAMB 2025

Calculate the time required to liberate 9g of Aluminium metal, when a current of 18A is passed through it.

(1F = 96500C , Al = 27)

  • A. 1769.17 minutes
  • B. 89.34 minutes
  • C. 5360.58 minutes
  • D. 29.48 minutes
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Correct Answer: Option B
Explanation

Al\(^{3+}\)  +  3e\(^-\) → Al

3e\(^-\) = 3F

3 F produced 27g of Al

3 x 96,500C produced 27g Al

(18 x t) C will produce 9g Al  (Recall that Q = I x t)

By simple proportion,

    \(\frac{3 x 96500}{18t}\) = \(\frac{27}{9}\)

     t = \(\frac{9 x 3 x 96500}{18 x 27}\)

     t = 5,361.11 seconds

Since the option is in minutes, we have to convert 5,361 seconds to minutes by dividing by 60 (60 sec = 1 min)

    t = \(\frac{5361}{60}\)

    t = 89.35 minutes

The correct answer is option B.

 

 

There is an explanation video available below.


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Explanation Video

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