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.

816.

Ripening of fruits is hastened by using

A.

Ethanol

B.

Ethane

C.

Ethene

D.

Ethyne

Correct answer is C

No explanation has been provided for this answer.

817.

When a compound X is heated with concentrated tetraoxosulphate(VI)acid, it produces an alkene. X ia an

A.

Alkane

B.

Alkanol

C.

Alkanoate

D.

Alkyne

Correct answer is B

No explanation has been provided for this answer.

818.

Amino acids are obtained from proteins by

A.

Hydrolysis

B.

Oxidation

C.

Polymerization

D.

Reduction

Correct answer is A

No explanation has been provided for this answer.

819.

Consider the following half-cell reactions.
Al(s) \(\to\) Al3+(aq) + 3e-
Cu2+(aq) + 2e- \(\to\) Cu(s)

The overall equation for the reaction is

A.

Al(s) + Cu2+(aq) \(\to\) Al3+(aq) + Cu(s)

B.

2Al(s) + Cu2+(aq) \(\to\) 2Al(aq) + Cu(s)

C.

2Al(s) + 3Cu2+(aq) \(\to\) 3Cu(s) + 2Al3+(aq)

D.

3Al(s) + 2Cu2+(aq) \(\to\) Cu(s) + 3Al3+(aq)

Correct answer is C

Al(s) \(\to\) Al3+(aq) + 3e- ______(i)
Cu2+(aq) + 2e- \(\to\) Cu(s) ________(ii)

To balance the electrons, multiply equation (i) by 2 and equation (ii) by 3 and then add the resulting equations

2Al(s) \(\to\)2Al3+(aq) + 3e-
3cu2+(aq) + 6e- \(\to\)3Cu(s)
2Al(s) + 3Cu2+(aq) \(\to\) 3Cu(s) + 2Al3+(aq)