Question 1

Four options are provided as possible answers to the following questions. Each  question has only ONE correct answer. Choose the answer and write only the letter (A–D) next to the question number (1.1–1.10) in the ANSWER BOOK, for example 1.11 E. 

1.1 Which ONE of the following pairs of reactants is used in a reaction during the  contact process? 

A N₂(g) and H₂(g) 

B SO₂(g) and O₂(g) 

C NH₃(g) and O₂(g) 

D H₂SO₄(ℓ) and NH₃(g) (2) 

1.2 The rate of a chemical reaction is most correctly defined as the … 

A time taken for a reaction to occur. 

B speed at which a reaction takes place. 

C change in the amount of reactants or products. 

D change in the concentration of reactants or products per unit time. (2) 

1.3 Consider the reaction represented by the balanced equation below. H₃PO₄(aq) + H₂O(ℓ) ⇌ H₃O⁺(aq) + H₂ ⁻ PO₄ (aq) 

Which ONE of the following is a conjugate acid-base pair? 

A H₃O⁺(aq) and H₂O(ℓ)  

B H₃PO₄(aq) and H₂O(ℓ)  

C H₃PO₄(aq) and H₃O⁺(aq)

D H₃O⁺(aq) and H₂ ⁻ PO₄ ^(aq) (2)

1.4 Which ONE of the following compounds has dipole-dipole forces between its molecules? 

A Ethanal 

B Ethane  

C Ethene 

D Ethyne (2)

1.5 The energy changes represented by P, Q and R on the potential energy  graph below take place during a reversible chemical reaction.

Which ONE of the following changes will decrease both P and R, but leave Q unchanged? 

A A decrease in volume  

B The addition of a catalyst 

C A decrease in temperature  

D A decrease in concentration (2) 

1.6 Which ONE of the following is a product formed during the hydrolysis of  bromoethane? 

A Water 

B Ethene 

C Ethanol 

D Bromine (2) 

1.7 Which ONE of the following is the EMPIRICAL FORMULA of  1,2-dichloroethane? 

A CHCℓ 

B CH₂Cℓ 

C CHCℓ₂ 

D C₂H₄Cℓ₂ (2)

1.8 The reaction represented by the balanced equation below reaches equilibrium  in a closed container. 

Cℓ₂(g) + H₂O(ℓ) ⇌ Cℓ^─(aq) + CℓO^─(aq) + 2H⁺(aq) 

Which ONE of the following reagents will favour the forward reaction when  added? 

A Hydrogen 

B Sodium chloride 

C Hydrogen chloride 

D Sodium hydroxide (2) 

1.9 The following half-reactions take place in a galvanic cell: 

Co³⁺ + e^– ⇌ Co²⁺ 

Aℓ³⁺+ 3e^– ⇌ Aℓ 

Which ONE of the following is the cell notation for this cell? 

A Aℓ ∣ Aℓ³⁺ ∥ Co³⁺, Co²⁺

B Aℓ ∣ Aℓ³⁺ ∥ Co³⁺, Co²⁺ ∣ Pt 

C Aℓ ∣ Aℓ³⁺ ∥ Co²⁺, Co³⁺ ∣ Pt 

D Pt ∣ Co²⁺ , Co³⁺ ∥ Aℓ³⁺ ∣ Aℓ (2)

1.10 Chlorine gas (Cℓ₂) is bubbled through a potassium iodide solution (KI). The  reducing agent in this reaction is:  

A Potassium ions 

B Chlorine gas 

C Iodide ions 

D Chloride ions (2)

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