Chemical Reactions Quiz

When silver chloride is exposed to sunlight, it turns grey. Which of the following best explains the change?

• Formation of silver sulphide

• Decomposition of AgCl into Ag and Cl₂

• Oxidation of silver to silver oxide

• Absorption of water from air

The rusting of iron is a:

• Physical change

• Double displacement reaction

• Redox reaction

• Endothermic reaction

In a reaction, A + B → AB, the temperature of the container increases. This means:

• Heat is absorbed, and the reaction is exothermic

• Heat is absorbed, and the reaction is endothermic

• Heat is released, and the reaction is exothermic

• Heat is released, and the reaction is endothermic

Which of the following equations is correctly balanced?

• Fe + H₂O → Fe₃O₄ + H₂

• 2Mg + O₂ → 2MgO

• Zn + HCl → ZnCl₂ + H₂

• C + O₂ → CO

Why does magnesium ribbon need to be cleaned before burning?

• To remove oil

• To remove water layer

• To remove oxide coating

• To increase ignition temperature

A student added dilute sulphuric acid to barium chloride solution. A white precipitate was formed. The reaction is an example of:

• Combination reaction

• Displacement reaction

• Double displacement reaction

• Oxidation-reduction reaction

Which of the following is/are an example of a redox reaction?

• 2KBr + Cl₂ → 2KCl + Br₂

• CaCO₃ → CaO + CO₂

• AgNO₃ + NaCl → AgCl + NaNO₃

• N₂ + 3H₂ → 2NH₃

Which of the following reactions represents both oxidation and reduction taking place simultaneously?

• CuO + H₂ → Cu + H₂O

• Zn(OH)₂ + HCl → ZnCl₂ + H₂O

• CaCO₃ → CaO + CO₂

• NaOH + HCl → NaCl + H₂O

Which of the following changes increases the rate of a chemical reaction?

• Decreasing temperature

• Decreasing surface area of reactants

• Adding a catalyst

• Removing reactants

When ferrous sulphate is heated strongly, it decomposes into ferric oxide, sulphur dioxide, and sulphur trioxide. This reaction is:

• Displacement reaction

• Thermal decomposition

• Redox reaction

• Neutralisation reaction