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Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

201.

A colored gas that is known to be poisonous and can readily damage the mucous lining of the lungs is?

A.

hydrogen sulphide

B.

carbon(ii)oxide

C.

chlorine

D.

sulphur(iv)oxide

Correct answer is C

Chlorine is a yellow-green gas at room temperature. Chlorine has a pungent, irritating odor similar to bleach that is detectable at low concentrations.

Exposure to low concentrations of chlorine (1 to 10 ppm) may cause eye and nasal irritation, sore throat, and coughing. Inhalation of higher concentrations of chlorine gas (>15 ppm) can rapidly lead to respiratory distress with airway constriction and accumulation of fluid in the lungs (pulmonary edema).

202.

An organic functional group which can likely decolorize ammoniacal silver nitrate is?

A.

alkene

B.

alkane

C.

alkyne

D.

alkanol

Correct answer is C

Terminal alkynes react with Tollens reagent (ammoniacal silver nitrate solution) to form silver alkynides as a white precipitate, whereas internal alkynes do not react with Tollens reagent.

203.

Zn + 2HCL → ZnCl2 + H2 

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

204.

N2O4 ⇔ 2NO2          (Δ = -ve)

From the reaction above, which of these conditions would produce the highest equilibrium yield for N2O4?

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 N2O4

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

205.

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

A.

RCONHR1

B.

RCONH2

C.

RNH2

D.

RCOR1

Correct answer is C

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

-Amine. R-NH2