No subcategories

Question from: Chemistry

What quantity of aluminium is deposited when a current of 10A is passed through a solution of an aluminium salt for 1930s?

[Al = 27, F = 96500 C mol-1]

A)  

0.2 g

B)  

1.8 g

C)  

5.4 g

D)  

14.2 g

Solutions

j

juanbacan

hace 2 meses

Solution

0

Got it — I’ll answer in English.

Correct answer: 1.8 g (Option B)

Explanation:

  • Cathode reaction: Al3+ + 3e → Al(s)
  • Charge passed: Q = I·t = 10 A × 1930 s = 19,300 C
  • Moles of electrons: ne− = Q/F = 19,300 / 96,500 = 0.20 mol e
  • Moles of Al: n(Al) = ne− / 3 = 0.20 / 3 ≈ 0.0667 mol
  • Mass of Al: m = nM = 0.0667 × 27 ≈ 1.8 g

Common pitfall: Forgetting to divide by 3 because Al3+ requires three electrons per atom deposited.

Add a solution

Don't miss the opportunity to help others. Register or log in to add a solution!

Show your knowledge

Help the community by answering some questions.

Practice with Simulators

Test your knowledge, solve these simulators similar to the exam

Do you need help with an exercise?

Ask a question and all of us in this community will answer it.

Ask