Assertion-reason questions

Directions: Please refer to the following instructions:

A Both statements are true and the 2nd statement is a correct explanation of the 1st

statement.

B Both statements are true but the 2nd statement is NOT a correct explanation of

the 1st statement.

C The 1st statement is false while the 2nd statement is true.

D Both statements are false.

1st statement 2nd statement

1 When zinc is added to dilute

hydrochloric acid, hydrogen is given

off.

Hydrogen chloride molecules contain

hydrogen atoms.

2 The basicity of ethanoic acid is 4. Each ethanoic acid molecule has four

hydrogen ions.

3 Dilute hydrochloric acid can conduct

electricity.

Dilute hydrochloric acid contains mobile

ions.

4 Gas bubbles are observed when sodium

carbonate is added to dilute

hydrochloric acid

Carbon dioxide is given off in the

reaction.

5 When a piece of copper metal is added

to dilute sulphuric acid, the solution

turns blue.

Copper reacts with dilute sulphuric acid

to form blue copper(II) sulphate solution.

6 Solid citric acid does not turn moist

blue litmus paper red.

Solid citric acid does not contain

hydrogen ions.

7 When solid citric acid is added to an

aqueous solution of sodium

hydrogencarbonate, the mixture fizzes.

When solid citric acid is dissolved in

water, citric acid molecules become

mobile.

8 Ethanoic acid is a non-electrolyte. Ethanoic acid is a covalent compound.

9 An aqueous solution of citric acid

contains mobile electrons.

Citric acid is an electrolyte.

10 To dilute a concentrated sulphuric acid,

water is added to the acid slowly.

A lot of heat energy will be given out in

the dilution of concentrated sulphuric

acid.

11 A brown precipitate is formed when

dilute sodium hydroxide solution is

added to iron(II) nitrate solution.

Dilute sodium hydroxide solution reacts

with iron(II) nitrate solution to form

insoluble iron(II) hydroxide.

12 When dilute potassium hydroxide

solution is added to sodium chloride

solution, a precipitate is formed.

The resulting solution contains potassium

ions.

13 Ammonia solution is an alkali. Ammonia solution turns red litmus paper

blue.

14 The pH value ammonia solution is

higher than that of hydrochloric acid of

the same concentration.

Every ammonia molecule contains three

hydrogen atoms while every hydrogen

chloride molecule contains one hydrogen

atom.

15 If a student accidentally spills some

sodium hydroxide solution onto his

hand, he should wash it with dilute

sulphuric acid.

Sulphuric acid can neutralize sodium

hydroxide solution.

16 Ethanoic acid is a weak acid while

hydrochloric acid is a strong acid.

2 M ethanoic acid has a pH value higher

than that of 2 M hydrochloric acid.

17 10 M ammonia solution is a strong

alkali.

10 M ammonia solution is corrosive.

18 Ammonia solution is a weak acid. Ammonia molecules partially ionize in

water to give hydrogen ions.

19 Protective gloves must be worn when

handling dilute sodium hydroxide

solution

Dilute sodium hydroxide solution is a

strong alkali.

20 10 cm3 of 1 M hydrochloric acid has a There are less mobile ions in 10 cm3 of1

lower electrical conductivity than 10

cm3 of 1 M ethanoic acid.

M hydrochloric acid than in 10 cm3 of 1

M ethanoic acid.

21 Ethanoic acid is a weak acid. Ethanoic acid is an organic acid.

22 Sulphuric acid is a strong acid while

ethanoic acid is a weak acid.

Sulphuric acid is dibasic while ethanoic

acid is monobasic.

23 Carbonic acid is a weak acid. Carbon dioxide is a covalent compound.

24 100 cm3 of 1 M ammonia solution has a

higher electrical conductivity than 100

cm3 of 1 M sodium hydroxide solution.

There are many mobile ammonia

molecules in ammonia solution.

25 Copper(II) hydroxide is a base. Copper(II) hydroxide reacts with acids to

give water and salt only.

26 Lead(II) oxide is an alkali. Lead(II) oxide is an ionic compound.

27 One mole of sulphuric acid can

completely neutralize one mole of

sodium hydroxide.

One mole of hydrogen ions reacts with

one mole of hydroxide ions to give water.

28 The reaction between sodium

hydrogencarbonate and dilute

hydrochloric acid is not a neutralization

reaction.

Apart from salt and water, carbon dioxide

is also produced in the reaction.

29 When dilute sodium hydroxide solution

is added to dilute sulphuric acid, the

temperature of the mixture rises.

Neutralization is an exothermic reaction.

30 When 10 cm3 of 1 M hydrochloric acid

are added to 10 cm3 of 1 M sodium

hydroxide solution, the concentration of

sodium ions in the mixture remains the

same.

When 10 cm3 of 1 M hydrochloric acid

are added to 10 cm3 of 1 M sodium

hydroxide solution, the only chemical

change is the reaction between H+(aq)

ions and OH-(aq) ions

to give water.

31 Sodium ethanoate (CH3COONa) is an Sodium ethanoate contains ionizable

acid salt. hydrogen atoms.

32 All salts are composed of metal ions

and non-metal ions.

All salts are ionic compounds.

33 All salts are soluble in water. All salts are ionic compounds.

34 Copper(II) sulphate cannot be prepared

by adding excess copper to dilute

sulphuric acid.

Copper does not react with dilute

sulphuric acid.

35 Calcium sulphate can be prepared by

mixing calcium chloride solution and

lead(II) sulphate solution.

Both calcium chloride and lead(II)

sulphate are soluble in water.

36 The salt formed in the reaction between

zinc oxide and dilute hydrochloric acid

can be obtained by filtration.

Zinc oxide is insoluble in water.

37 Sodium hydroxide is not used as the

active ingredient in antacids.

Sodium hydroxide reacts with

hydrochloric acid to produce sodium

chloride.

38 Tablets of antacid should be chewed

before swallowing.

Chewing increases the surface area of the

tablets so that they react with

hydrochloric acid in the stomach at a

faster rate.

39 Sodium hydroxide solution is added to

factory waste to remove metal ions.

Sodium hydroxide solution can neutralize

the acidity of factory waste.

40 Ammonium sulphate is used to remove

the acidity of soil.

Ammonium sulphate gives an alkaline

solution when it is dissolved in water.

41 Benzoic acid is commonly found in

canned grapefruit juice.

Benzoic acid is toxic to bacteria.

42 Adding lime to alkaline soil can

increase crop yield

Lime acts as a fertilizer for the soil.

43 The pH value of 10 cm3 of 1 M The number of moles of hydrogen ions in

hydrochloric acid is lower than that of

10 cm3 of 2 M hydrochloric acid.

10 cm3 of 1 M hydrochloric acid is less

than that in 10 cm3 of 2 M hydrochloric

acid.

44 In 1 dm3 of 1 M sodium nitrate solution,

there is one mole of ions.

Every mole of sodium nitrate contains

one mole of ions.

45 Measuring cylinder can be used to

measure 25.0 cm3 of hydrochloric acid

for titration.

A measuring cylinder gives accurate

readings of volume.

46 Before filling a burette with an acid, the

burette is washed with distilled water

only.

Distilled water can wash away the

impurities on the inner wall of the

burette.

47 When filling a pipette with a solution, a

pipette filler is preferred over sucking

with the mouth.

A 25.0 cm3 pipette can transfer exactly

25.0 cm3 of a solution.

48 In acid-alkali titrations, before filling a

pipette with an alkali, the pipette is

washed with distilled water only.

Impurities inside the pipette will affect

titration results.

49 The amount of hydrogen produced by

the reaction between 10 cm3 of 10 M

hydrochloric acid and excess

magnesium is greater than produced by

the reaction between 100 cm3 of 1 M

hydrochloric acid and excess

magnesium.

10 M hydrochloric acid is a stronger acid

1 M hydrochloric acid.

50 10 cm3 of 1 M ethanoic acid require less

number of moles of sodium hydroxide

for complete neutralization than 10 cm3

of 1 M hydrochloric acid.

Ethanoic acid is a weak acid while

hydrochloric acid is a strong acid.

51 The reaction between powdered

magnesium and dilute hydrochloric acid

is slower than that between magnesium

ribbons of the same mass and dilute

The surface area of magnesium ribbons is

greater than that of magnesium powder of

the same mass.

hydrochloric acid.

52 The rate of reaction between sodium

carbonate and dilute hydrochloric acid

can be followed by measuring the mass

of the reaction mixture at regular time

intervals.

Water is produced in the reaction between

sodium carbonate and dilute hydrochloric

acid.

53 The rate of reaction between aluminium

hydroxide and dilute sulphuric acid can

be followed by measuring the mass of

the reaction mixture at regular time

intervals.

The mass of the reaction mixture

decreases as the reaction proceeds.

54 The rate of reaction between zinc and

dilute hydrochloric acid can be

followed by measuring the volume of

gas given off at regular time intervals.

Hydrogen gas is produced in the reaction

between zinc and dilute hydrochloric

acid.

55 100 cm3 of 1 M hydrochloric acid react

with excess zinc granules at the same

rate as 100 cm3 of 1 M sulphuric acid.

Both hydrochloric acid and sulphuric acid

are strong acids.