JAMB Past Questions and Answers - Page 1470

7,346.

When an element can exist in two or more forms in the same physical state, the element is said to exhibit

A.

isotopy

B.

isomerism

C.

allotropy

D.

hygroscopy

E.

sublimation

Correct answer is C

No explanation has been provided for this answer.

7,347.

Given that for the reaction KOH (aq) + HCI(aq) → KCI(aq) + H2O(L) H = - 54 Kj mol-1. What is the quantity of heat involved in the reaction?2NaOH(aq) + H2SO 4(aq) → Na2SO4(aq) + 2H 2O(l)?

A.

- 108Kj

B.

-54 kj

C.

-27 kj

D.

+27 kj

E.

+54 kj

Correct answer is A

Given that \(KOH_{(aq)} + HCl_{(aq)} \to KCl_{(aq)} + H_{2}O_{(l)} ; \Delta H = -54 kJ/mol\)

The standard heat of neutralization is the amount of heat evolved when 1 mole of hydrogen ion from an acid reacts with 1 mole of hydroxide ion from the base to form one mole of water, under standard conditions.

\(\therefore 2NaOH_{(aq)} + H_{2}SO_{4(aq)} \to Na_{2}SO_{4(aq)} + 2H_{2}O_{(l)} ; \Delta H = -(2 \times 54 kjmol^{-1})\)

\(\therefore \Delta H = -108 kJmol^{-1}\) 

7,348.

Which of the following gases will bleach moist litmus paper?

A.

CI2

B.

CO2

C.

SO2

D.

HCI2

E.

N2 O

Correct answer is A

No explanation has been provided for this answer.

7,349.

How many carbon atoms are there in a benzene ring?

A.

4

B.

5

C.

6

D.

7

E.

8

Correct answer is C

No explanation has been provided for this answer.

7,350.

If 200cm 3 of a gas at s.t.p. has a mass of 0.268g, what is its molar mass? (Molar volume of a gas at s.t.p. = 22.4 dm3)

A.

300g

B.

200g

C.

150g

D.

30g

E.

15g

Correct answer is D

No explanation has been provided for this answer.