JAMB Chemistry Past Questions & Answers - Page 86

426.

The compound above exhibits

A.

Geometric isomerism

B.

Positional isomerism

C.

Structural isomerism

D.

Optical isomerism

Correct answer is D

Optical isomers are molecules that are non-superimposable mirror images of each other and they are not identical. Molecules with a chiral carbon show this kind of isomerism. Chiral carbon, also known as asymmetric carbon, refers to carbon atom that are bonded to four different atoms or groups of atoms.

427.

MnO\(_4\)(aq) + Y + 5Fe\(^{2+}\) (aq) \(\mapsto\) Mn\(^{2+}\) (aq) + 5Fe\(^{3+}\) (aq) + 4H\(_2\)O (l).

In the equation above, Y is

A.

10H+ (aq)

B.

5H+ (aq)

C.

8H+ (aq)

D.

4H+ (aq)

Correct answer is C

No explanation has been provided for this answer.

428.

A chemical reaction in which the hydration energy is greater than the lattice energy is referred to as

A.

A reversible reaction

B.

A spontenous reaction

C.

An endothermic reaction

D.

An exothermic reaction

Correct answer is D

In salts for which the hydration energy is higher than the lattice energy, solvation occurs with a release of energy in the form of heat. A reaction in which there is a release of energy as LIGHT OR HEAT is EXOTHERMIC.

429.

The gas that is used for the treatment of cancer is

A.

Neon

B.

Radon

C.

Xenon

D.

Argon

Correct answer is B

No explanation has been provided for this answer.

430.

Calculate the volume in cm3 of oxygen evolved at s.t.p when a current of 5A is passed through acidified water for 193s?
[F = 96500 C mol1. Molar volume of a gas at s.t.p = 22.4dm3]

A.

0.056dm3

B.

0.224dm3

C.

224.000dm3

D.

56.000dm3

Correct answer is A

Q = 193 x 5 = 965C
40H \(\mapsto\) 2H2O + O2 + 4e
4 x 96500C = 22.4dm3
965C = x

x = \(\frac{22.4 \times 965}{4 \times 96500}\)
= 0.056dm3