Physics 2013 JAMB Past Questions - Question 45: If a current of 2.5A flows through an electrolytes for 3 hours and 1.8g of a substance is deposited ,what is the mass of the substance that will be deposited if a current of 4A flows through it for 4.8hours ?

Correct Answer

C

Explanation

To find the mass of the substance deposited, we can use Faraday's law of electrolysis. According to Faraday's law, the mass of a substance deposited is directly proportional to the amount of charge passed through the electrolyte.

The formula to calculate the mass of a substance deposited is:

Mass = (Current × Time × Atomic Mass) / (Faraday's Constant)

Given:
Current 1 = 2.5 A
Time 1 = 3 hours
Mass 1 = 1.8 g

We can calculate the constant of proportionality (K) using the given data:

K = Mass 1 / (Current 1 × Time 1)

Now, we can use the constant of proportionality to find the mass of the substance deposited with the new current and time:

Current 2 = 4 A
Time 2 = 4.8 hours

Mass 2 = K × (Current 2 × Time 2)

Let's calculate the mass of the substance deposited with the new current and time:

K = 1.8 g / (2.5 A × 3 hours)
K ≈ 0.24 g/(A·h)

Mass 2 = 0.24 g/(A·h) × (4 A × 4.8 hours)
Mass 2 ≈ 4.61 g

Therefore, if a current of 4A flows through the electrolyte for 4.8 hours, approximately 4.61 grams of the substance will be deposited.