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.

1,141.

In countries where the temperature fall below 273k, salt always spilled on the road in order to

A.

increase the boiling point

B.

increase the density of the ice

C.

make the ice impure

D.

reduce the freezing point of ice

Correct answer is D

No explanation has been provided for this answer.

1,142.

Alloys are best prepared by

A.

electroplating

B.

Arc-welding

C.

reducing and mixture of their metallic

D.

cooking a molten of the metals

Correct answer is D

Alloy is a metal that consist of two or more metals mixed together e.g. is mass which is an alloy of copper and zinc. Are not prepared with option A,B,C, and the do not result in mixture and metals together

1,143.

Electronic configuration of an element 13 in the subsidiary energy level is

A.

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

B.

\( 1s^22s^2 2p^4 3p^1 3s^1 \)

C.

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

D.

\( 1s^1 2s^2 2p^6 3s^2 3p^4 \)

Correct answer is A

No explanation has been provided for this answer.

1,144.

Which of the following gives a precipitation when treated with NaOH Solution?

A.

AlCl3

B.

NH4Cl

C.

Na2CO3

D.

CH3COONa

Correct answer is A

AlCl3 will give a precipitate when treated with solution. Option B,C,D will not give a precipitate when treated with NaOH solution

1,145.

PCL5(g)= PCL3(g) + Cl2(g)

In the reaction above, a decrease in pressure will

A.

Decelerate the reaction

B.

Increase yield of Pcl3

C.

Increase the yield of Pcl5

D.

Accurate the reaction

Correct answer is B

If we decrease the pressure in the reaction, there will be rapid breakage spilling of pcl5. And these follows a principle that molecule of gases tends to move from a region of higher pressure to low pressure. Option A,C,D will not be affected by pressure decrease