NECO Chemistry Past Questions & Answers - Page 11

51.

During the electrolysis of sodium Chloride solution, hydrogen is discharged at the carbon cathode because

A.

hydrogen ions are in greater concentration than sodium ions.

B.

hydrogen is higher than sodium in the electrochemical series.

C.

hydrogen is lower than sodium in the electrochemical series.

D.

of the nature of the electrodes.

E.

the concentration of sodium ions is greater than that of the hydrogen ion in the electrolyte.

Correct answer is C

No explanation has been provided for this answer.

52.

Which of these is NOT a physical property f water?

A.

Can be used to dissolve organic substances

B.

Has a boiling point of 100 ° C

C.

Has a density of 19cm3 at 40 °C

D.

Has a freezing point of 0 ° C

E.

is neutral to litmus

Correct answer is A

No explanation has been provided for this answer.

53.

The following gases are diatomic EXCEPT

A.

Fluorine

B.

Helium

C.

Hydrogen

D.

Nitrogen

E.

Oxygen

Correct answer is B

No explanation has been provided for this answer.

54.

If two elements X and Z with electronic configurations 2,8.3 and2,8,6 respectively combine, the compound formed will have the formula

A.

XZ

B.

XZ2

C.

X2Z

D.

X2Z3

E.

X3Z2

Correct answer is D

No explanation has been provided for this answer.

55.

The reaction of hydrochloric acid and calcium trioxocarbonate (IV) produces

A.

calcium chloride, carbon (IV) oxide and water

B.

calcium chloride, and trioxocarbonate (IV) acid

C.

calcium hydroxide, carbon (IV) oxide and chlorine gas

D.

calcium hydroxide, carbon (IV) oxide and water

E.

calcium metal and water.

Correct answer is A

No explanation has been provided for this answer.