Learners' AlleyDesigned by Khow Willard

Acids and Bases

Set AFoundations

Name

Time 45 minutes

Total 23 marks

Use a copy of the Periodic Table where you need one.

From the lesson

9 marks

A green powder is added to dilute hydrochloric acid. It fizzes and the gas turns limewater milky. What type of substance is the powder?

Aa metal

Ba metal oxide

Ca carbonate

Dan alkali

Answer [1]

Source: Learners' Alley, Acids and Bases slides

Which pair of substances gives off ammonia when heated together?

Aammonium chloride and hydrochloric acid

Bammonium sulfate and sodium hydroxide

Csodium chloride and sodium hydroxide

Dammonium nitrate and water

Answer [1]

Source: Learners' Alley, Acids and Bases slides

Solution P has pH 2 and solution Q has pH 5. Which statement is correct?

AQ is more acidic than P.

BP has a higher concentration of H⁺ ions than Q.

CBoth turn Universal Indicator green.

DQ is alkaline.

Answer [1]

Source: Learners' Alley, Acids and Bases slides

Which element forms an oxide that dissolves in water to give a solution with a pH below 7?

Acopper

Bmagnesium

Csulfur

Dsodium

Answer [1]

Source: Learners' Alley, Acids and Bases slides

Answer these questions about acids, alkalis and oxides.

(a)

Define an acid.

[1]

(b)

Write the ionic equation, with state symbols, for neutralisation.

[1]

(c)

State the difference between a strong acid and a weak acid.

[2]

(d)

Classify aluminium oxide and give a reason.

[1]

Source: Learners' Alley, Acids and Bases slides

Practice

14 marks

An aqueous solution has a pH value of 1. What information does this fact imply about the ions present in the solution?

	concentration of H⁺ ions	concentration of OH⁻ ions
A	high	low
B	high	none
C	low	high
D	low	none

Answer [1]

Source: 2023 HYSS Sec 3 End-of-Year P1 Q12

Which statement about an alkali is incorrect?

AIt reacts with a carbonate to form carbon dioxide.

BIt reacts with an acid to form a salt.

CIt reacts with an ammonium salt to form ammonia.

DIt turns Universal Indicator blue.

Answer [1]

Source: 2023 HYSS Sec 3 End-of-Year P1 Q14

Which row correctly classifies the nature of these oxides?

	aluminium oxide	nitrogen dioxide	sodium oxide
A	amphoteric	basic	acidic
B	basic	acidic	amphoteric
C	amphoteric	acidic	basic
D	acidic	amphoteric	basic

Answer [1]

Source: 2023 GESS Sec 3 End-of-Year P1 Q29

A farmer wishes to grow some ceanothus flowers. The pH of his soil is 5.1. Ceanothus flowers are known to grow best at around pH 7.2. Which substance should he add to his soil for the ceanothus to grow well?

Acalcium hydroxide

Bcitric acid

Csodium hydroxide

Dwater

Answer [1]

Source: 2023 GESS Sec 3 End-of-Year P1 Q30

Both magnesium carbonate and magnesium oxide react with dilute sulfuric acid. In what way are both reactions the same?

AA gas is produced.

BAn acid is neutralised by a soluble base.

CSulfuric acid is acting as an oxidising agent.

DWater is a product.

Answer [1]

Source: 2024 CHS Sec 3 End-of-Year Section A Q23

The table shows information about three indicators. Which colour would each indicator show if it were added separately to pure water?

indicator	colour change	pH at which colour changes
methyl yellow	red to yellow	3
bromocresol green	yellow to blue	5
thymolphthalein	colourless to blue	9

	methyl yellow	bromocresol green	thymolphthalein
A	red	blue	blue
B	red	yellow	blue
C	yellow	blue	colourless
D	yellow	yellow	colourless

Answer [1]

Source: 2023 XMS Sec 3 WA3 Q5

Which equation suggests that a metal oxide, RO, behaves as an amphoteric oxide?

ARO(s) + 2H⁺(aq) → R²⁺(aq) + H₂O(l)

BRO(s) + 2OH⁻(aq) → RO₂²⁻(aq) + H₂O(l)

CRO(s) + H₂O(l) → R²⁺(aq) + 2OH⁻(aq)

DRO(s) + 2NH₄⁺(aq) → R²⁺(aq) + H₂O(l) + 2NH₃(g)

Answer [1]

Source: 2024 SMSS Sec 3 End-of-Year P1 Q12

In an accident at a factory, some dilute acid was spilt. Which substance, when added in excess, removes the acid without leaving an alkaline solution?

Aaqueous ammonia

Baqueous sodium hydroxide

Csolid ammonium nitrate

Dsolid calcium carbonate

Answer [1]

Source: 2024 CHS Sec 3 End-of-Year Section A Q24

Choose from the following substances to answer the questions: Al₂O₃, NaCl, N₂, Pb(NO₃)₂, SO₂. Each substance may be used once, more than once or not at all.

(a)

Select the amphoteric oxide.

[1]

(b)

Select the acidic oxide.

[1]

Source: 2023 XMS Sec 3 WA3 Q6, adapted

Hydrochloric acid is a strong acid with pH 1 while ethanoic acid is a weak acid with pH 5.

(a)

What is meant by the term weak acid?

[1]

(b)

Starting with acids of the same concentration, describe a chemical test that you can conduct to show that sulfuric acid is a strong acid but ethanoic acid is a weak acid. Include in your answer the chemicals you use, the expected observations and the conclusion.

[3]

Source: SJI 2020 Year 3 End-of-Year P2 B8(a)