JAMB Chemistry Past Questions & Answers - Page 22

106.

Zn + 2HCL → ZnCl\(_2\) + H\(_2\) 

What happens to zinc in the above reaction?

A.

oxidized

B.

a reactant

C.

reduced

D.

a metal

Correct answer is A

-Zn is a reducing agent, HCl is an oxidizing agent.

-the zinc is oxidized

107.

N\(_2\)O\(_4\) ⇔ 2NO\(_2\)          (Δ = -ve)

From the reaction above, which of these conditions would produce the highest equilibrium yield for N\(_2\)O\(_4\)?

A.

Low temperature and high pressure

B.

Low temperature and low pressure

C.

high temperature and low pressure

D.

high temperature and high pressure

Correct answer is D

high temperature and high pressure favor the highest yield for N\(_2\)O\(_4\)

high temperature favours the production of the reactant since it is endothermic, while high pressure favours the side involving a decrease in volume.

108.

An organic compound with fishy smell is likely to have a general formula?

A.

RCONHR\(^1\)

B.

RCONH\(_2\)

C.

RNH\(_2\)

D.

RCOR\(^1\)

Correct answer is C

Amines possess a characteristic ammonia smell, liquid amines have a distinctive "fishy" and foul smell. 

-Amine. R-NH2

109.

Using the metal activity series, the metal that can liberate hydrogen gas from steam is?

A.

iron

B.

copper

C.

tin

D.

lead

Correct answer is A

Iron reacts with steam to form iron oxide and hydrogen gas.

110.

Addition of charcoal to the filter bed of sand during water treatment for township supply is to?

A.

prevent goiter

B.

prevent tooth decay

C.

remove odour

D.

kill germs

Correct answer is C

Activated Carbon filters are excellent at removing chlorine and related poor taste and odor.