JAMB Chemistry Past Questions & Answers - Page 100

496.

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.

497.

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.

498.

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

499.

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

500.

According to the kinetic theory an absence in temperature causes the kinetic energy of particles to

A.

decrease

B.

increase

C.

remain constant

D.

be zero

Correct answer is D

No explanation has been provided for this answer.