NECO Chemistry Past Questions & Answers - Page 13

61.

A chemical system is at equilibrium when

A.

δ G is positive

B.

δ G is zero

C.

δ S is negative

D.

δ S is positive

E.

δ S is zero.

Correct answer is B

No explanation has been provided for this answer.

62.

When sodium hydroxide solution is added to a solution of zinc salt, the white precipitate formed re-dissolve in excess sodium hydroxide because

A.

sodium hydroxide is a strong alkali

B.

sodium is more reactive than zinc

C.

zinc is more reactive than sodium

D.

zinc hydroxide is amphoteric

E.

zinc hydroxide is unstable

Correct answer is D

No explanation has been provided for this answer.

63.

The gas in air used by plants for photosynthesis is

A.

Argon

B.

Carbon (IV) oxide

C.

Nitrogen

D.

Oxygen

E.

Water vapour.

Correct answer is B

No explanation has been provided for this answer.

64.

Which of these arrangement of elements is in order of increasing ionization energy?

A.

Boron, Carbon, Flourine, Nitrogen

B.

Boron, Carbon, Nitrogen, Flourine

C.

Carbon, Boron, Nitrogen, Flourine

D.

Flourine, Nitro9en, Carbon, Boron

E.

Nitrogen, Flourine, Carbon, Boron

Correct answer is B

No explanation has been provided for this answer.

65.

The following acids are monobasic EXCEPT

A.

dioxonitrate (Ill) acid

B.

ethanedioic acid

C.

hydrobromic acid

D.

methanoic acid

E.

oxochlorate (I) acid

Correct answer is B

No explanation has been provided for this answer.