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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.

656.

If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?

A.

lead oxide

B.

Magnesium oxide

C.

Copper oxide

D.

Tin oxide

Correct answer is B

The oxides of Potassium, Sodium, Calcium, and Magnesium are not reduced when they react with carbon and hydrogen.

657.

What volume of oxygen will remain after reacting 8cm3 of hydrogen gas with 20cm3 of oxygen gas

A.

10cm3

B.

12cm3

C.

14cm3

D.

16cm3

Correct answer is D

No explanation has been provided for this answer.

658.

Suitable reagents for the laboratory preparation of nitrogen are

A.

sodium dioxonitrate(III) and ammonium chloride

B.

sodium trioxonitrate(V) and ammonium chloride

C.

sodium chloride and ammonium trioxonitrate(V)

D.

sodium chloride and ammonium di-ozonitrate(III)

Correct answer is A

No explanation has been provided for this answer.

660.

Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?

A.

Extractive distillation

B.

Filtration followed by distillation

C.

Neutralization with sodium hydroxide followed by distillation

D.

Neutralization with sodium hydroxide followed by filtration

Correct answer is A

Due to the presence of maximum Azeotrope,we use extractive distilination (with extractive distilation agents like sulfone) used for mixtures with low relative volatility,nearing unity.

Azeotrope is a mixture of liquids that has a constant boiling point because the vapour has thesame composition as the mixture.