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.

3,231.

What quantity of aluminum is deposited when a current of 10A is passed through a solution of an aluminum salt for 1930s?
[Al = 27, F = 96500 C mol -1]

A.

0.2 g

B.

1.8 g

C.

5.4 g

D.

14.2 g

Correct answer is B

Q = It = 10 x 1930 ( given)

27g → 3F( since aluminum is trivalent)

27g → 3 x 96500

x → 19300

x = \(\frac{27 \times 19300}{3 \times 96500}\)

x = 1.8g

3,232.

Iron can be protected from corrosion by coating the surface with?

A.

gold

B.

silver

C.

copper

D.

zinc

Correct answer is D

No explanation has been provided for this answer.

3,233.

The IUPAC nomenclature of the compound LiAlH4 is?

A.

lithiumtetrahydridoaluminate (III)

B.

aluminium tetrahydrido lithium

C.

tetrahydrido lithium aluminate (III)

D.

lithium aluminium hydride

Correct answer is A

No explanation has been provided for this answer.

3,234.

6AgNO4(aq) + PH3(g) + 3H2O(l) → 6Ag(s) + H3PO3(g) + 6HNO3(aq)
In the above reaction, the reducing agent is?

A.

HNO3(aq)

B.

H2O(l)

C.

PH3(g)

D.

AgNO3(aq)

Correct answer is C

Phosphorus(iii)hydride is a strong reducing agent which reduces solution of silver or copper(ii)salts to the metals or phosphides.

3,235.

Which of the following salts is slightly soluble in water?

A.

AgCl

B.

CaSO4

C.

Na2CO3

D.

PbCl2

Correct answer is B

All sulfates are soluble except those of barium, strontium and lead. Calcium sulfate, silver sulfate and mercurous sulfate are slightly soluble in water, but calcium sulfate is rarely precipitated in reactions between the calcium and sulfate ions.