Chemical Reactions and Equations (Fill in the blanks and MCQs)

• (a) and (b)

• (a) and (c)

• (a), (b) and (c)

• all.

Answer explanation

Note: (c) and (d) are correct.

• combination reaction.

• double displacement reaction.

• decomposition reaction.

• displacement reaction

What happens when dilute hydrochloric acid is added to iron fillings?

• Hydrogen gas and iron chloride are produced.

• Chlorine gas and iron hydroxide are produced.

• No reaction takes place.

• Iron salt and water are produced.

What is a balanced chemical equation? Why should chemical equations be balanced?

Translate the following statements into chemical equations and then balance them:

(a) Hydrogen gas combines with nitrogen to form ammonia.

(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide.

(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.

(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Balance the following chemical equations:

(a) HNO₃ + Ca(OH)₂ ⟶ Ca(NO₃)₂ + H₂O

(b) NaOH + H₂SO₄ ⟶ Na₂SO₄ + H₂O

(c) NaCl + AgNO₃ ⟶ BaSO₄ + HCl

(d) BaCl₂ + H₂SO₄ ⟶ BaSO₄ + HCl

What does one mean by exothermic reactions? Give examples.

What does one mean by endothermic reactions? Give examples.