Acids, Bases and Salts: common misconceptions

If your child says… “I can taste an unknown liquid to test it.”

Ask together

How could you test it without putting it in your mouth?

What’s true

Unknown solutions may be poisonous or corrosive.

If your child says… “Acids always release hydrogen when something fizzes.”

Ask together

Does fizzing alone tell us which gas has formed?

What’s true

Carbonates and hydrogencarbonates release carbon dioxide when reacting with acids.

If your child says… “Every oxide acts as a base.”

Ask together

Which reacts with a base: copper oxide or carbon dioxide?

What’s true

Many metal oxides are basic, while many non-metal oxides are acidic.

If your child says… “Water neutralises acid.”

Ask together

Which hydronium ions disappear between the two vessels?

What’s true

Dilution lowers ion concentration without the acid reacting with a base.

If your child says… “A higher pH means more acid.”

Ask together

Is the enamel-damaging value above or below the neutral value?

What’s true

Acid damage to enamel begins below about pH 5.5.

If your child says… “Every salt solution is neutral.”

Ask together

Do both salts have the same parents?

What’s true

Sodium carbonate has weak acid and strong base parents, so its solution is basic.

If your child says… “Only sodium hydroxide forms.”

Ask together

Which gases leave the two electrodes?

What’s true

Electrolysis also produces chlorine and hydrogen.

If your child says… “Plaster hardens by drying.”

Ask together

Does the arrow show water leaving the crystals or becoming part of them?

What’s true

Setting forms gypsum with water in its crystal structure.