Courses » WAEC » WAEC Chemistry » Chemistry Exam Topics » 1993 - Questions and Answers

1993 - WAEC Chemistry Past Questions and Answers - page 2

11

In which of the following changes is ∆S negative ?

A
H2O(l) → H2O(s)
B
C(s) + 1/2O2,/sub>(g) → CO(g)
C
PCI5(g) → PCl3(g) + Cl2(g)
D
NaCl(s) + aq →Na+ (aq) + Cl- (aq)
Ask EduPadi AI for a Detailed Answer
12

Chlorine is is used in water treatment as

A
a germicide
B
a decolorizing agent
C
an antioxidant
D
a coagulating agent
Ask EduPadi AI for a Detailed Answer
13

Which of the following pieces of deposited if a current of 10A was passed through a solution of copper(ll) salt for 965 seconds? (1F = 96500 C)

A
0.005 mole
B
0.025 mole
C
0.05 mole
D
1.00 mole
Ask EduPadi AI for a Detailed Answer
14

Some precious stones such as ruby and sapphire consist of aluminum oxide coloured by traces of the oxides of

A
group lV elements
B
group l metals
C
transition metals
D
alkaline earths
Ask EduPadi AI for a Detailed Answer
15

Consider the reaction represented by the following equation CaCI2 (aq) + H 2C2O 4(aq) ⇌ CaC 2O4(s) + 2HCI(aq). Which of the following would dissolve the precipitate of CaC 2O4 formed?

A
Stirring the mixture vigorously
B
Adding more calcium chloride solution
C
lncreasing the concentration of the ethanedioic acid
D
Adding concentrated hydrochloric acid
Ask EduPadi AI for a Detailed Answer
16

The following gases decolorize bromine water except

A
C2H6
B
C2H4
C
C2H2
D
C3H4
Ask EduPadi AI for a Detailed Answer
17

What volume of distilled water should be added to 400cm3 of 2.0 mole dm-3 \(H_{2}SO_{4}\) to obtain 0.20 mole dm-3 of solution>

A
600cm-3
B
800cm-3
C
1,000cm-3
D
3,600cm-3
Ask EduPadi AI for a Detailed Answer
18

Which of the following indicates the correct increasing order of oxidizing power of the halogens?

A
F < CI < Br < l
B
l < Br < CI < F
C
I < CI < Br < F
D
Br < I < CI < F
Ask EduPadi AI for a Detailed Answer
19

Which of the following substances is a peroxide?

A
Na2O2
B
CuO
C
PbO4
D
Fe2O
Ask EduPadi AI for a Detailed Answer
20

The component of air that removed when air is bubbled into alkaline pyrogallol solution is

A
carbon(lV) oxide
B
oxgyen
C
water vapour
D
nitrogen
Ask EduPadi AI for a Detailed Answer
Please share this, thanks: