An alloy contains copper and zinc. Some of the zinc has become oxidized to zinc oxide. What is the result of adding an excess of dilute sulfuric acid to the alloy?
1. A blue solution and a white solid remains.

2. A colorless solution and a pink / brown solid remains.

3. The alloy dissolves completely to give a blue solution.

4. The alloy dissolves completely to give a colorless solution.

Expert Answers

| Certified Educator

The reactivity of copper is much less than that of zinc. While zinc can react with dilute sulfuric acid copper does not react with dilute sulfuric acid, it only reacts with concentrated sulfuric acid.

The alloy is made up of copper and zinc; some of the zinc has oxidized to zinc oxide. Zinc reacts with dilute sulfuric acid following the chemical reaction: Zn + H2SO4 --> ZnSO4 + H2. Zinc oxide reacts with dilute sulfuric acid following the chemical reaction ZnO + H2SO4 --> ZnSO4 + H2O.

ZnSO4 is a colorless compound that dissolves in water. Copper settles to the bottom as a pink/brown solid.

When the alloy made of copper and zinc is reacted with dilute sulfuric acid the result is a colorless solution and a pink/brown solid lying at the bottom of the container.

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