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.

466.

Consider the reaction: A + 2B\(_{(g)} \rightleftharpoons \) 2C + D\(_{(g)}\) (\(\Delta\)H = +ve)

What will be the effect of decrease in temperature on the reaction?

A.

Rate of backward reaction will increase

B.

The equilibrium constant will shift

C.

Rates of forward and backward reactions are not affected

D.

Rate of forward reaction will increase

Correct answer is A

The given reaction is endothermic, hence, a decrease in temperature will favor the exothermic side which is the backward reaction.

467.

The following are isoelectronic ions except

A.

Na\(^+\)

B.

Mg\(^{2+}\)

C.

Si\(^{2+}\)

D.

O\(^{2+}\)

Correct answer is C

Two or more ions are said to be isoelectronic if they have the same electronic structure and the same number of valence electrons.

Na\(^+\) = 10 electrons = 2, 8

Mg\(^{2+}\) = 10 electrons = 2,8

O\(^{2-}\) = 10 electrons = 2,8

Si\(^{2+}\) = 12 electrons = 2,8,2

\(\implies\) Si\(^{2+}\) is not isoelectronic with the rest.

468.

The hybridization in the compound \(CH_3 - CH_2 - C \equiv H\) is

A.

sp\(^3\) and sp

B.

sp

C.

sp\(^2\)

D.

sp\(^3\) and sp\(^2\)

Correct answer is A

The hybridization in a and b is sp\(^3\) hybridization while in c and d is sp hybridization.

469.

The electronic configuration of element Z is 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\). What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion.

A.

Z\(_3\)(SO\(_4\))\(_2\)

B.

ZSO\(_4\)

C.

Z\(_2\) SO\(_4\)

D.

Z\(_2\)(SO\(_4\))\(_3\)

Correct answer is D

Z = 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\)

\(\therefore\) We have Z\(^{3+}\) and SO\(_4 ^{2-}\)

The reaction : Z\(^{3+}\) + SO\(_4 ^{2-}\) \(\to\) Z\(_2\)(SO\(_4\))\(_3\).

470.

Which of the following could not be alkane?

A.

C\(_4\)H\(_{10}\)

B.

C\(_5\)H\(_{12}\)

C.

C\(_7\)H\(_{14}\)

D.

C\(_8\)H\(_{18}\)

Correct answer is C

No explanation has been provided for this answer.