St Peter the Apostle High SchoolChemistry Department
Acids and Alkalis
N4 & N5 Homework Questions
National 4 Questions
1.As a homework exercise, pupils were asked to find the pH values of a number of
substances found in the home.
One pupil wrote down her results as follows:
Bicarbonate of soda – 9; vinegar – 4; drain cleaner – 14; cola drink – 3; milk – 8;
indigestion pill – 10; window cleaner – 12; washing up liquid – 7; lemon juice – 3;
Present the results of the home exercise in two different ways. (2,2)
2.Decide whether each of the following statements is:
A. True B. False
(a) pH 4 is more acidic than pH 6
(b) pH 8 is more alkaline than pH 10
(c) pH 3 is less acidic than pH 1
(d) pH 13 is more alkaline than pH 11(4)
3.A student carried out an experiment to find the pH values of different garden soils.
Water was slowly poured through a sample of soil and a solution was collected.
(a) How would the student then find the pH of the solution?(1)
(b) The pH values of the garden soils are shown.
(i) Which garden has the most alkaline soil?(1)
(ii) Copy and complete by choosing the correct word:
The pH of soil B can be increased by adding acid/salt/alkali/alcohol.(1)
4.As water is added to an acid, the acid becomes
A more acidic and its pH goes down
B more acidic and its pH goes up
C less acidic and its pH goes up
D less acidic and its pH goes down(1)
5.Which oxide, when shaken with water, would leave the pH unchanged?
You may wish to use page 8 of the data booklet.
A calcium oxideB carbon dioxide
C sulfur dioxideD zinc oxide(1)
6.The grid contains the names of some compounds.
(a)Identify the two compounds which contain three elements.(1)
(b)Identify the compound which dissolves in water to form an alkaline solution.(1)
(c)Identify the compound which reacts with water to form acid rain.(1)
7.Consider the following list:
iron (III) oxide, sodium hydroxide, carbon dioxide,
calcium oxide, nitrogen dioxide, copper (II) oxide
(a) Name two substances which dissolve to produce a solution which has pH
below 7.
(b) Name two substances which dissolve to produce a solution which has pH
above 7.(4)
8.(a) What name is given to any substance which will neutralise an acid?(1) (b) If the substance in part (a) is soluble, what is it specifically called? (1)
9.Name the acid and alkali which could be used to prepare a solution of:
(a) sodium nitrate
(b) potassium sulfate(2)
10.Sodium hydroxide+ sulfuric acidsalt + water
The name of the salt produced in this reaction is
A hydrogen sulfate
B hydrogen sulfide
C sodium sulfate
D sodium sulfide(1)
11.Which salt is produced when calcium carbonate is used to neutralise nitric acid?
A calcium nitrateB calcium chloride
C calcium sulfateD calcium phosphate(1)
12.(a) Name the salt formed in the following reactions
(b) Write a word equation for each reaction
(i)hydrochloric acid and lithium hydroxide
(ii)sulfuric acid and copper carbonate
(iii)nitric acid and barium oxide
(iv)phosphoric acid and sodium hydroxide (4,4)
13.Which of the following potassium compounds is a base?
A potassium nitrateB potassium chloride
C potassium sulfateD potassium carbonate(1)
14.Which of the following gases in the atmosphere will contribute to the greenhouse effect?
A carbon dioxideB sulfur dioxide
C oxygenD nitrogen(1)
15.Many pollution problems are linked to the release of sulfur dioxide into the air.
(a)Name one source of sulfur dioxide in air.(1)
(b)What name is given to a solution of sulfur dioxide in rain-water.(1)
(c)Give three examples of the damage which can be caused by this solution.(1)
(d)(i) Name one other gas which causes similar pollution problems.(1)
(ii) Give one source of this gas.(1)
16.Which of the following pairs of chemicals react to produce a gas that turns lime water
cloudy?
A calcium carbonate and dilute hydrochloric acid
B copper oxide and dilute sulfuric acid
C copper and dilute hydrochloric acid
D magnesium and dilute sulfuric acid(1)
17.Indigestion can be caused by the stomach producing toomuch acid. Indigestion
tablets can help by neutralising the acid.
(a)Copy and complete the sentence by choosing the correct ending:
As acid is neutralised, the pH goes up towards 7/goes down towards 7/stays at 7.(1)
(b)(i) Neutralisation can be carried out in a test tube.
Which test tube could be used to compare the effect of crushing the indigestion
tablets on the speed of the reaction?
(1)
(ii) What could be used to show an acid has been neutralised?(1)
18.Slaked lime can be added to lochs to reduce acidity.
(a)What causes the lochs to become acidic?(1)
(b)Slaked lime can be made from limestone.
(i) Name the elements present in calcium carbonate.(1)
(ii) Suggest a name for chemical X.(1)
National 5 Questions
- Some indicators can have different colours when in solutions of different pH values.
The tables give information about two indicators, bromothymol blue and methyl
orange.
The pH of three solutions was investigated using both indicators. The results are
shown below.
(a)Which solution is alkaline? (1)
(b)Suggest a pH value for solution B. (1)
2.Explain why crystals of citric acid have no effect on dry pH paper but turn universal
indicator red. (1)
3.An acidic solution contains
A only hydrogen ions
B only hydroxide ions
C more hydrogen ions than hydroxide ions
D more hydroxide ions than hydrogen ions(1)
4.Acid solutions contain H+(aq) ions; so does pure water.
(a) Explain why pure water is not an acid.(1)
(b) When water is added to an acid solution the pH rises.
(i) Explain why this happens.(1)
(ii) What is the highest value to which the pH can rise?(1)
(iii) Explain your answer to (ii).(1)
5.Which line in the table describes what happens to a dilute solution of hydrochloric
acid when water is added to it?
(1)
6.Which of the following oxides dissolves in water to produce a solution with a pH
greater than 7?
A Na2OB Al2O3 C SO2D Ag2O(1)
7.Chlorine reacts with water.
Cl2(g) + H2O(l)2H+(aq)+OCl-(aq)+Cl-(aq)
What happens to the pH of water when it is chlorinated?(1)
8.John spilled sulfuric acid from a car battery on his garage floor. First he poured water
over the acid. Then he sprinkled washing soda (sodium carbonate) on it before
mopping it up.
(a) Why did John add water to the acid?(1)
(b) (i) Name the type of reaction which takes place when washing soda is added to the
sulfuric acid.(1)
(ii) Name the gas produced in the reaction.(1)
(c) Write a balanced chemical equation for the reaction between washing soda and
sulfuric acid.(2)
9.Sodium nitrate and sodium carbonate are both white solids. Using your knowledge of chemistry describe how you could discover which was which if you were given a sample
of each (describe and give results of any experiments you could carry out and write
balanced chemical equations ). (3)
10.Crystals of magnesium sulfate can be made by adding excess magnesium oxide
to dilute sulfuric acid.
(a) What happens to the pH and the hydrogen ion concentration of the acid during the reaction? (1)
(b) Describe how the excess magnesium oxide can be removed from the solution.(1)
(c) Write a balanced chemical equation for the reaction. (2)
11.Chromic acid, H2CrO4 (aq) forms a salt with potassium hydroxide.
(a)How many moles of potassium hydroxide would be needed to neutralise
completely one mole of chromic acid?(1)
(b)Name the salt formed in the reaction.
(You may wish to use page 8 of the data booklet)(1)
12.
(1)
13.
(1)
14.For the following reaction:
(i)identify the spectator ions
(ii)remove the spectator ions to write the ion electron equation
NaOH (aq)+HCl (aq)NaCl (aq)+H2O (l)(2)
15.(a) Write out a balanced chemical equation for the reaction between nitric acid
and potassium carbonate.(2)
(b) Identify the spectator ions.(1)
(c) Rewrite the equation omitting the spectator ions.(1)
16.An insoluble product can be formed in the reaction between solutions.
(a)Name this type of reaction.(1)
(b)Identify the insoluble product in eachof the following reactions
(i)potassium sulfate solution and barium chloride solution
(ii)lead (II) nitrate solution and sodium sulfate solution
(iii)sodium chloride solution and silver nitrate solution.(3)
(c)For each reaction abovewrite a balanced chemical equation and identify the
spectator ions.(9)
17.(a)How many moles of potassium hydroxide are required to make 200cm3 of
solution, concentration 0.5 moll-1?(2)
(b)What is the concentration of a solution of phosphoric acid, made by dissolving
0.5 moles of pure acid and making up to 250cm3 with water?(2)
(c)What volume of a solution, concentration 0.2 moll-1, contains 0.05 mol of solute?(2)
(d)The gram formula mass of phosphoric acid is 98g.
If 49g of phosphoric acid is dissolved in water and the solution made up to 200cm3,
what is the concentration of the resulting solution?(3)
(e)What mass of pure sodium nitrate is needed to make 1 litre of solution,
concentration 0.2moll-1? (3)
18.If 25cm3 of sodium hydroxide solution is neutralised by 14.4cm3 of nitric acid,
concentration 0.22 moll-1, what is the concentration of the alkali?
NaOH (aq) +HNO3 (aq)NaNO3 (aq) +H2O (l)(3)
19.What volume of potassium hydroxide solution, concentration 0.08 moll-1 will be
neutralised by 17.6cm3 of sulfuric acid, concentration 0.1 moll-1?
2KOH (aq)+H2SO4 (aq)K2SO4 (aq) +2H2O (l)(3)
20.What volume of nitric acid, concentration 0.12 moll-1 is required to neutralise 20cm3
of potassium hydroxide solution, concentration 0.1 moll-1?(3)
21.If 20cm3 of sodium hydroxide solution is neutralised by 15.6cm3 of sulfuric acid,
concentration 0.1 moll-1, what is the concentration of the alkali?(3)