NECO Past Questions and Answers - Page 80

396.

Atomic size decreases

A.

across a period from left to right

B.

across a period from right to left

C.

diagonally down the group

D.

down a group

E.

with decrease in atomic number

Correct answer is A

No explanation has been provided for this answer.

397.

Sulphur has an oxidation number of +4 in

A.

H2S

B.

H2S04

C.

MgSO4

D.

Na2SO3

E.

S03

Correct answer is D

No explanation has been provided for this answer.

398.

If the volume of a gas at 35°C is 60cm3, what would be its volume in cm3 at 273k?

A.

39.03

B.

46.81

C.

53.18

D.

67.69

E.

76.92

Correct answer is C

No explanation has been provided for this answer.

399.

C\(_6\)H\(_{12}\)O\(_6\)

What is the molar mass of the compound above?

[ H=1, C=12, O=16 }

A.

45

B.

61

C.

180

D.

123

E.

244

Correct answer is C

The compound above is identified as glucose

Carbon - 12 \(\times\) 6 atoms present

Hydrogen - 1 \(\times\) 12 atoms present

Oxygen - 16 \(\times\) 6 atoms present

= 72 + 12 + 96

= 180

400.

In the electrolysis of dilute tetraoxosulphate (VI) acid using platinum electrodes, the products obtained at the anode are cathode respectively are

A.

hydrogen, oxygen

B.

Hydrogen, tetraoxosulphate (VI) ion

C.

oxygen, hydrogen

D.

sulphur, hydrogen

E.

sulphur, oxygen

Correct answer is C

No explanation has been provided for this answer.