Acids and Bases

• Chemistry
• Secondary Education

TEMPLATE

Topic 9/10 - Acids and Bases

Acids and Bases

08 December 2025

How do you feel today?

😒🙁😐🙂😃

TEMPLATE

• I will know the difference between acids and bases.
• I will understand why acids have a lower pH and bases have a higher pH.

Which of the following is NOT an acid?

1. NH₄Cl
2. H₂SO₄
3. HCl
4. HNO₃

Acids, especially concentrated acids, are _________. You need eye protection and gloves to protect yourself.

1. flammable
2. corrosive
3. volatile
4. neutral

What makes an acid acidic?

1. OH⁻ ions
2. H⁺ ions
3. Cl⁻ ions
4. high pH

All acids form H⁺ ions when we dissolve them in water. 

True or False.

1. True
2. False

TEMPLATE

HCl (g) + H₂O(l) → H⁺(aq) + Cl⁻(aq)

TEMPLATE

HCl (g) + H₂O(l) → H⁺(aq) + Cl⁻(aq)

Write an equation to show how nitric acid forms H⁺ ions.

A ________________ is defined as a generally insoluble substance which can neutralise an acid.

1. base
2. acid
3. alkali
4. salt

Which of the following is NOT a base?

1. metal oxides
2. ammonia
3. non-metal oxides
4. metal hydroxides

Which of the following is NOT a base?

1. Ca(OH)₂
2. H₂SO₄
3. NaOH
4. KOH

________ are corrosive bases that are SOLUBLE in water.

1. Bases
2. Salts
3. Alkalis
4. Acids

TEMPLATE

NaOH (s) + H₂O(l) → Na⁺(aq) + OH⁻(aq)

TEMPLATE

Write an equation to show how potassium hydroxide forms OH⁻ ions.

NaOH (s) + H₂O(l) → Na⁺(aq) + OH⁻(aq)

NaOH (s) + H₂O(l) → Na⁺(aq) + OH⁻(aq)

HCl (g) + H₂O(l) → H⁺(aq) + Cl⁻(aq)

Why does an alkali neutralise an acid?

proton donor

proton acceptor

H⁺(aq)

OH⁻(aq)

_____________ change colour, indicating whether a solution is acidic or alkaline. They can’t measure pH.

1. Solutions
2. Indicators
3. Mixtures
4. Compounds

TEMPLATE

pH and indicators

Thymolphthalein

The _______________ is a measure of a measure of how acidic or alkaline a solution is.

1. universal indicator
2. pH scale
3. natural indicators
4. colour wheel

The ___________ is SPECIAL because it changes colour at different pH values, so it CAN be used to give an approximate pH.

1. universal indicator
2. pH scale
3. natural indicators
4. colour wheel

TEMPLATE

Colour of the universal indicator at

different pH values

TEMPLATE

Work in groups:

Complete the Investigation Tasks with your teammates.

How well did you participate in

 the lesson today?

05

TEMPLATE

Assesses student comprehension through a worksheet, quiz, a lab report, or a concluding class discussion.