NECO Chemistry Past Questions & Answers - Page 22

106.

Which metal bromide is widely used in photography?

A.

calcium bromide

B.

magnesium bromide

C.

potassium bromide

D.

silver bromide

E.

sodium bromide

Correct answer is D

No explanation has been provided for this answer.

107.

What change will occur during the electrolysis of brine using carbon electrodes?

A.

Chlorine will be given off at the anode

B.

Oxygen gas will be given off at the anode

C.

Sodium will be deposited at the cathode

D.

The resulting solution, after electrolysis, will be acidic.

E.

The volumes of hydrogen and chlorine given off during the same time are equal

Correct answer is A

Chlorine is discharged as follows:

\(Cl^- \to Cl + e^-\)

\(Cl + Cl \to Cl_{2(g)}\)

This reaction occurs at the anode.

108.

Which metal is a constituent of both bronze and solder?

A.

copper

B.

lead

C.

silver

D.

tin

E.

zinc

Correct answer is D

No explanation has been provided for this answer.

109.

An atom of element X has an electronic configuration of \( 1s^22S^22p^63s^23p^3. \) In which group of the periodic table is X?

A.

0

B.

2

C.

3

D.

4

E.

5

Correct answer is E

You can determine the group of an element by the number of electrons of their outermost shell.

Hence; this element silicon belongs to group 5 OR The Group to which an element belongs to, can be identified by adding the number of electrons of the orbital with the highest principal quantum number, in this case, 3s2 and 3p3. Therefore, 2+3 is equal to 5

note; if the highest principal quantum number is just 3s2 for example then the element belong to group 2. 

110.

What mass of silver is deposited when a current of 2.6 A is passed through a solution of a silver salt for 40 minutes? [Ag= 108 ; F=96500C]

A.

6.89g

B.

6.93g

C.

6.98g

D.

7.04g

E.

7.12g

Correct answer is C

No explanation has been provided for this answer.