Year : 
2010
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

21 - 30 of 49 Questions

# Question Ans
21.

6AgNO4(aq) + PH3(g) + 3H2O(l) → 6Ag(s) + H3PO3(g) + 6HNO3(aq)
In the above reaction, the reducing agent is?

A. HNO3(aq)

B. H2O(l)

C. PH3(g)

D. AgNO3(aq)

Detailed Solution

Phosphorus(iii)hydride is a strong reducing agent which reduces solution of silver or copper(ii)salts to the metals or phosphides.
There is an explanation video available below.
22.

The IUPAC nomenclature of the compound LiAlH4 is?

A. lithiumtetrahydridoaluminate (III)

B. aluminium tetrahydrido lithium

C. tetrahydrido lithium aluminate (III)

D. lithium aluminium hydride

Detailed Solution

There is an explanation video available below.
23.

Iron can be protected from corrosion by coating the surface with?

A. gold

B. silver

C. copper

D. zinc

Detailed Solution

There is an explanation video available below.
24.

What quantity of aluminum is deposited when a current of 10A is passed through a solution of an aluminum salt for 1930s?
[Al = 27, F = 96500 C mol -1]

A. 0.2 g

B. 1.8 g

C. 5.4 g

D. 14.2 g

Detailed Solution

There is an explanation video available below.
25.

In which of the following is the entropy change positive?

A. Thermal dissociation of ammonium chloride

B. Reaction between an acid and a base

C. Addition of concentrated acid to water

D. Dissolution of sodium metal in water

Detailed Solution

Thermal dissociation of ammonium chloride is an endothermic reaction as heat is absorbed for a positive entropy, with more products than reactants.
There is an explanation video available below.
26.

If a reaction is exothermic and there is a great disorder, it means that?

A. the reaction is static

B. the reaction is in a state of equilibrium

C. there will be a large increase in free energy

D. there will be a large decrease in free energy

Detailed Solution

If a reaction is exothermic and there is a great disorder for a spontaneous reaction to occur, a large decrease in free energy is evident.
There is an explanation video available below.
27.

In the preparation of oxygen by heating KClO3 in the presence of MnO2, only moderate heat is needed because the catalyst acts by?

A. lowering the pressure of the reaction

B. increasing the surface area of the reactant

C. increase the rate of the reaction

D. lowering the energy barrier of the reaction

Detailed Solution

- The presence of MnO2 increase the rate of the reaction by providing a new reaction path / making more particles possess kinetic energy greater then the activation energy.
There is an explanation video available below.
28.

The graph above demonstrate the effect of?

A. surface area on the rate of reaction

B. catalyst on the rate of reaction

C. pressure on the rate reaction

D. concentration on the rate of reaction

Detailed Solution

There is an explanation video available below.
29.

2H2(g) + O2(g) ⇌ 2H2O(g) ΔH = -ve
what happens to the equilibrium constant of the reaction above if the temperature is increased?

A. it is unaffected

B. it becomes zero

C. it decrease

D. it increase

Detailed Solution

This given equation shows the forward reaction is exothermic, which means an increase in temperature will cause the equilibrium position to shift to left to favor reactant formation, i.e K decreases
There is an explanation video available below.
30.

To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of?

A. CO\(^{2-}_{3}\)

B. Cl-

C. SO\(_{3}^{2-}\)

D. NO\(^{2-}_{3}\)

Detailed Solution

NO\(_{3}^{-}\) is confirmed, then the brown ring is due to the formation of FESO\(_4\).NO
There is an explanation video available below.
21.

6AgNO4(aq) + PH3(g) + 3H2O(l) → 6Ag(s) + H3PO3(g) + 6HNO3(aq)
In the above reaction, the reducing agent is?

A. HNO3(aq)

B. H2O(l)

C. PH3(g)

D. AgNO3(aq)

Detailed Solution

Phosphorus(iii)hydride is a strong reducing agent which reduces solution of silver or copper(ii)salts to the metals or phosphides.
There is an explanation video available below.
22.

The IUPAC nomenclature of the compound LiAlH4 is?

A. lithiumtetrahydridoaluminate (III)

B. aluminium tetrahydrido lithium

C. tetrahydrido lithium aluminate (III)

D. lithium aluminium hydride

Detailed Solution

There is an explanation video available below.
23.

Iron can be protected from corrosion by coating the surface with?

A. gold

B. silver

C. copper

D. zinc

Detailed Solution

There is an explanation video available below.
24.

What quantity of aluminum is deposited when a current of 10A is passed through a solution of an aluminum salt for 1930s?
[Al = 27, F = 96500 C mol -1]

A. 0.2 g

B. 1.8 g

C. 5.4 g

D. 14.2 g

Detailed Solution

There is an explanation video available below.
25.

In which of the following is the entropy change positive?

A. Thermal dissociation of ammonium chloride

B. Reaction between an acid and a base

C. Addition of concentrated acid to water

D. Dissolution of sodium metal in water

Detailed Solution

Thermal dissociation of ammonium chloride is an endothermic reaction as heat is absorbed for a positive entropy, with more products than reactants.
There is an explanation video available below.
26.

If a reaction is exothermic and there is a great disorder, it means that?

A. the reaction is static

B. the reaction is in a state of equilibrium

C. there will be a large increase in free energy

D. there will be a large decrease in free energy

Detailed Solution

If a reaction is exothermic and there is a great disorder for a spontaneous reaction to occur, a large decrease in free energy is evident.
There is an explanation video available below.
27.

In the preparation of oxygen by heating KClO3 in the presence of MnO2, only moderate heat is needed because the catalyst acts by?

A. lowering the pressure of the reaction

B. increasing the surface area of the reactant

C. increase the rate of the reaction

D. lowering the energy barrier of the reaction

Detailed Solution

- The presence of MnO2 increase the rate of the reaction by providing a new reaction path / making more particles possess kinetic energy greater then the activation energy.
There is an explanation video available below.
28.

The graph above demonstrate the effect of?

A. surface area on the rate of reaction

B. catalyst on the rate of reaction

C. pressure on the rate reaction

D. concentration on the rate of reaction

Detailed Solution

There is an explanation video available below.
29.

2H2(g) + O2(g) ⇌ 2H2O(g) ΔH = -ve
what happens to the equilibrium constant of the reaction above if the temperature is increased?

A. it is unaffected

B. it becomes zero

C. it decrease

D. it increase

Detailed Solution

This given equation shows the forward reaction is exothermic, which means an increase in temperature will cause the equilibrium position to shift to left to favor reactant formation, i.e K decreases
There is an explanation video available below.
30.

To a solution of an unknown compound, a little dilute tetraoxosulphate (VI) acid was added with some freshly prepared iron (II) tetraoxosulphate (VI) solution. The brown ring observed after the addition of a stream of concentrated tetraoxosulphate (VI) acid confirmed the presence of?

A. CO\(^{2-}_{3}\)

B. Cl-

C. SO\(_{3}^{2-}\)

D. NO\(^{2-}_{3}\)

Detailed Solution

NO\(_{3}^{-}\) is confirmed, then the brown ring is due to the formation of FESO\(_4\).NO
There is an explanation video available below.