Exams › NEET › Chemistry

Al2O3 is reduced by electrolysis at low potentials and high currents. If 4.0 × 10⁴ amperes of current is passed through molten Al2O3 for 6 hours, what mass of aluminium is produced? (Assume 100% current efficiency and At. mass of Al = 27 g mol⁻¹)

1. 8.1 × 10³ g
2. 2.4 × 10⁵ g
3. 1.3 × 10⁴ g
4. 9.0 × 10³ g

Correct answer: 8.1 × 10³ g

Solution

Using Faraday's laws of electrolysis, the mass of Al produced is calculated as: m = (Z × I × t), where Z = M / (n × F). For Al, n = 3. Substituting values: m = (27 / (3 × 96500)) × (4.0 × 10⁴) × (6 × 3600) = 8.1 × 10³ g.

Related NEET Chemistry questions

• Assertion: When an electric current is passed through the copper sulphate electrolyte, the impure copper anode gradually dissolve and pure copper is deposited on the cathode. Reason: Pure metals are deposited in electroplating techniques.
• What is the electric current required to deposit 0.972 g of chromium in three hours? (E.C.E. of chromium is 0.00018 g/c)
• Which of the following statement (s) differentiate between electrochemical cell and electrolytic cell? This question has multiple correct options
• Among the following, the couple with most positive reduction potential is :
• The resistance of \( 1 \mathrm{N} \) solution of acetic acid is \( 250 \Omega \) when measured in a cell having a cell constant of \( 1.15 \mathrm{cm}^{-1} . \) The equivalent conduction (in oh \( m^{-1} c m^{2} e q u i v^{-1} \) ) of \( 1 N \) acetic acid is
• If \( 9 g m H_{2} O \) is electrolysed completely with the current of \( 50 \% \) efficiency then :

⚔️ Practice NEET Chemistry free + battle 1v1 →