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Reviewed CSCA Chemistry question · Standard

Which of the following equations is correctly balanced for the reaction between aluminum and sulfuric acid to produce aluminum sulfate and hydrogen gas?

  1. 2 Al + 3 H2SO4 → Al2(SO4)3 + 3 H2
  2. Al + H2SO4 → AlSO4 + H2
  3. 2 Al + 3 H2SO4 → Al2(SO4)3 + H2
  4. 2 Al + 2 H2SO4 → Al2(SO4)3 + 3 H2
Show the answer and explanation

Correct answer

A. 2 Al + 3 H2SO4 → Al2(SO4)3 + 3 H2

Principle or equation

A balanced chemical equation must have the same number of each type of atom on both sides. The correct formulas must be used: aluminum sulfate is Al2(SO4)3, and hydrogen gas is H2.

Why this answer is correct

Option A: Left: 2 Al, 6 H, 3 S, 12 O. Right: 2 Al, 6 H, 3 S, 12 O. All atoms balance. The other options either have incorrect formulas or unbalanced atom counts.

Example

Balancing Al + HCl → AlCl3 + H2: 2 Al + 6 HCl → 2 AlCl3 + 3 H2.

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