G2 Acid-Base Chemistry

Ions, indicators, pH, acid reactions, neutralisation, applications and oxide classification.

SEC G2 Science Chemistry component 2027

Work through the lessons below in teaching order; each one says what it covers.

Acids, bases, alkalis and indicators
Use aqueous ions and raw indicator observations to distinguish acidic, neutral and alkaline solutions.
Acid reactions and neutralisation
Predict products, connect gas observations to reactions, and explain neutralisation with ions and balanced equations.
Applications and oxide behaviour
Choose a soil treatment and classify oxides from their acid and alkali reactions.

Strong- and weak-acid ionisation, salt preparation and ammonia manufacture are outside this G2 family. Your explanations should stay with aqueous ions, indicator and pH evidence, prescribed reaction patterns, neutralisation, applications and oxide classification.

Learning goals

describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
describe neutrality and relative acidity and alkalinity, in terms of — relative H+ and OH– ion concentrations,
describe neutrality and relative acidity and alkalinity, in terms of — colour in Universal Indicator, and
describe neutrality and relative acidity and alkalinity, in terms of — the pH scale (calculation of pH from hydrogen ion concentration is not required)
describe the characteristic properties of acids as in reactions with metals, bases and carbonates to form salts (description of the preparation of pure salts is not required)
describe the reaction between hydrogen ions and hydroxide ions to produce water, H+ + OH– → H2O, as neutralisation
describe the characteristic properties of bases in reactions with acids and with ammonium salts
describe the importance of controlling the pH in soils and how excess acidity can be treated using calcium hydroxide
classify oxides as acidic, basic, amphoteric or neutral based on metallic/non-metallic character.

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About 8 minutes

Answer 4 short questions. It shows what to work on next and doesn't count towards mastery.

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Which statement correctly combines the aqueous ion definitions of acids and alkalis with the basis for classifying oxides?

Acids produce H⁺(aq), alkalis produce OH⁻(aq), and every metal oxide is classified as basic without reaction evidence.
Acids produce H⁺(aq), alkalis produce OH⁻(aq), and acid–base reaction evidence classifies oxides.
Acids produce OH⁻(aq), alkalis produce H⁺(aq), and acid–base reaction evidence classifies oxides.
Acids produce H⁺(aq), every base is an alkali, and acid–base reaction evidence classifies oxides.

What are the products when a suitable metal reacts with dilute hydrochloric acid?

A salt, water and carbon dioxide.
A metal oxide and oxygen.
A salt and hydrogen.
A salt and water only.

Which net ionic equation represents neutralisation between an acid and an alkali?

$\ce{H+(aq)}$ + $\ce{OH-(aq)}$ → $\ce{H2O(l)}$
$\ce{Na+(aq)}$ + $\ce{Cl-(aq)}$ → $\ce{NaCl(aq)}$
$\ce{H2O(l)}$ → $\ce{H+(aq)}$ + $\ce{OH-(aq)}$
$\ce{NH4+(aq)}$ → $\ce{NH3(g)}$ + $\ce{H+(aq)}$

Why can calcium hydroxide be used to treat acidic soil?

It supplies hydrogen ions to the soil
It neutralises excess acid in the soil
It releases carbon dioxide into the soil
It prevents salts from forming in the soil

Practise

Work through questions with marking and feedback as you learn.

About 10 minutes

Questions are picked at random each time you start. You'll see the answer after each question. It's for practice only and doesn't count towards mastery.

Recent attempts

History is stored only in this browser.

No completed attempts are saved yet.

This check needs JavaScript to record answers. The reviewed questions are listed below for study.

Which statement correctly combines the aqueous ion definitions of acids and alkalis with the basis for classifying oxides?

Acids produce H⁺(aq), alkalis produce OH⁻(aq), and every metal oxide is classified as basic without reaction evidence.
Acids produce H⁺(aq), alkalis produce OH⁻(aq), and acid–base reaction evidence classifies oxides.
Acids produce OH⁻(aq), alkalis produce H⁺(aq), and acid–base reaction evidence classifies oxides.
Acids produce H⁺(aq), every base is an alkali, and acid–base reaction evidence classifies oxides.

An aqueous solution at room temperature has pH 3. Which conclusion is correct?

It is acidic; its pH is below 7.
It is alkaline because 3 is a small number.
It must turn every named indicator red.
It is neutral because every single-digit pH is neutral.

Which gas is released when an ammonium salt is warmed with aqueous sodium hydroxide?

Carbon dioxide from every ammonium ion.
Ammonia.
Hydrogen in every case.
Hydroxide ions as a gas.

What are the products of an acid reacting with a carbonate?

A salt and hydrogen.
A base and oxygen.
A salt and oxygen only.
A salt, water and carbon dioxide.

Which reaction is evidence that an oxide shows basic behaviour?

Its element is a metal, with no reaction evidence needed.
It reacts with neither an acid nor a base.
It reacts with an acid to form a salt and water.
It reacts only with a base.

Why can calcium hydroxide be used to treat acidic soil?

It supplies hydrogen ions to the soil
It neutralises excess acid in the soil
It releases carbon dioxide into the soil
It prevents salts from forming in the soil

Hydrochloric acid reacts with aqueous sodium hydroxide, an alkali, to form a salt and water. What is this type of reaction called?

Displacement
Neutralisation
Thermal decomposition
Precipitation

Practise after feedback

After a check, practise the skills it showed you need to work on.

About 10 minutes

Questions are picked at random each time you start. You'll see the answer after each question. It's for practice only and doesn't count towards mastery.

Recent attempts

History is stored only in this browser.

No completed attempts are saved yet.

This check needs JavaScript to record answers. The reviewed questions are listed below for study.

Which statement correctly combines the aqueous ion definitions of acids and alkalis with the basis for classifying oxides?

Acids produce H⁺(aq), alkalis produce OH⁻(aq), and every metal oxide is classified as basic without reaction evidence.
Acids produce H⁺(aq), alkalis produce OH⁻(aq), and acid–base reaction evidence classifies oxides.
Acids produce OH⁻(aq), alkalis produce H⁺(aq), and acid–base reaction evidence classifies oxides.
Acids produce H⁺(aq), every base is an alkali, and acid–base reaction evidence classifies oxides.

An aqueous solution at room temperature has pH 3. Which conclusion is correct?

It is acidic; its pH is below 7.
It is alkaline because 3 is a small number.
It must turn every named indicator red.
It is neutral because every single-digit pH is neutral.

Which gas is released when an ammonium salt is warmed with aqueous sodium hydroxide?

Carbon dioxide from every ammonium ion.
Ammonia.
Hydrogen in every case.
Hydroxide ions as a gas.

What are the products of an acid reacting with a carbonate?

A salt and hydrogen.
A base and oxygen.
A salt and oxygen only.
A salt, water and carbon dioxide.

Which reaction is evidence that an oxide shows basic behaviour?

Its element is a metal, with no reaction evidence needed.
It reacts with neither an acid nor a base.
It reacts with an acid to form a salt and water.
It reacts only with a base.

Why can calcium hydroxide be used to treat acidic soil?

It supplies hydrogen ions to the soil
It neutralises excess acid in the soil
It releases carbon dioxide into the soil
It prevents salts from forming in the soil

Hydrochloric acid reacts with aqueous sodium hydroxide, an alkali, to form a salt and water. What is this type of reaction called?

Displacement
Neutralisation
Thermal decomposition
Precipitation

Check my progress

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About 10 minutes

Answer 6 questions. You'll see your score, the answers and explanations at the end. Your result can count towards your course progress.

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Answer 6 questions. You'll see your score, the answers and explanations at the end. A scheduled review counts towards your course progress only when it is due.

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G2 Acid-Base Chemistry

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