What mass of magnesium would be obtained by passing a current of 2 amperes for 2 hours 30 mins, through molten magnesium chloride?

[1 faraday = 96500C, Mg = 24]

  • A 1.12g
  • B 4.48g
  • C 1.80g
  • D 2.00g
jamb 2019chemistry

The correct answer is D. 2.00g

Given  Data:

Time (T) = 2hrs 30mins 

where 2hrs =120mins

2hrs & 30mins = (120 + 30)mins = 150mins

150mins to Seconds = 150 x60 = 9,000s

Q = I x T

2 x 9,000 =18,000

where mg has valency of +2

So 2 x 96500 will discharge 24g of mg

and 18,000 will discharge xg of mg

2 x 96500 =24

18,000 =x

x = \(\frac{24 \times 18,000}{2 x 96500}\)

≈ 2.00g

Previous question Next question