TEST1
Click on the correct answer
1
Common household bleaches include
1. chlorine bleach
2. bleaching powder
3. sulphurous acid
1 and 2
1 and 3
2 and 3
all the options
2
Which of the following is commonly used as a household germicide?
Baking soda solution
Bleaching solution
Sodium chloride
Vinegar
3
To wash clothes with washing machines, bleaching solution is often added besides washing powder. The purpose of using bleaching solution is to
1. remove greasy spots from clothes
2. remove coloured stains from clothes
3. give added whiteness to clothes
1 only
3 only
2 and 3
all the options
4
When diluted hydrochloric acid is added to a chlorine bleach,
1. a gas is given out and that turns moist blue litmus paper red and then white
2. there is a smell of 'swimming pool'
3. a brown precipitate is given
1 and 2
1 and 3
2 and 3
all the options
5
Which of the following can be prepared by the laboratory electrolysis of concentrated sodium chloride solution using graphite electrode?
1. Sodium
2. Chlorine
3. Sodium hydroxide
1 and 2
1 and 3
2 and 3
all the options
6
Chlorine water may be prepared by
1. bubbling chorine through water until it is saturated with the gas
2. mixing equal volumes of bench dilute hydrochloric acid and commercial bleaching solution and then diluting with water
3. adding excess dilute hydrochloric acid to sodium chloride
1 and 2
1 and 3
2 and 3
all the options
7
Which method is the most suitable way to obtain bromine from sodium bromide present in sea water?
Adding dilute nitric acid
Adding potassium hydroxide
Heating the sea water
Adding chlorine
8
On storage, chlorine water will slowly change to
Dilute sodium chloride solution
Dilute sodium hydroxide solution
Sodium hypochlorite solution
Dilute hydrochloric acid
9
Which of the following is true of sulphur dioxide?
It is insoluble in water
It can be used to bleach flour
It is sweet smelling
It has no effect on the moist litmus paper
10
Which of the following properties apply to sulphur dioxide?
1. It changes the colour of iron ( III ) sulphate solution from pale brown to pale green
2. It decolorize bromine water
3. It bleaches dry litmus paper
1 and 2
1 and 3
2 and 3
all the options
11
The ideal pH range for the swimming pool water is between
6.4 and 7.0
7.2 and 7.8
8.2 and 8.7
8.9 and 9.5
12
Which of the following can be used as a germicide for swimming pools?
1. Ozone
2. Chlorine
3. Chlorine bleach
1 and 2
2 and 3
1 and 3
all the options
13
What gas is produced if household bleach is accidentally mixed with a toilet cleaner containing hydrochloric acid?
Hydrogen
Chlorine
Oxygen
Bromine
14
What is the main reason that a higher concentration of chlorine is required for swimming pool water in summer than in winter?
More chlorine will be lost if the water is warmer
There are more germs in the pool water in summer
There are more people swim in summer
Chlorine works better as a germicide at a lower temperature
15
In Hong Kong, 1 dm
3
of drinking water usually contain 0.8 mg dm
-3
of chlorine.
What volume of chlorine measured at room condition is dissolved in 1 m
3
of drinking water?
( atomic mass: Cl=35.5; molar volume of a gas at room conditions = 24 dm
3
mol
-1
)
27 cm
3
50 cm
3
270 cm
3
500 cm
3