1.1. Acids are substances that turn universal indicator paper red.

i) What makes a substance acidic?

[1]

ii) Sodium hydroxide, NaOH, is an alkali.

Sodium hydroxide neutralises sulfuric acid, H₂SO₄. The reaction makes a salt called sodium sulfate, Na₂SO₄. Water is also made.

Complete the balanced symbol equation for this reaction.

........ NaOH + H₂SO₄ → Na₂SO₄ + ........ H₂O

[2]

1.2. A student investigates the reaction of an aqueous solution of sodium hydroxide and sulfuric acid. During the experiment, the student tests the pH of the solution with universal indicator.

i) Suggest a piece of equipment that the student could use instead of universal indicator paper to test the pH of the solution.

[1]

ii) Describe how to use the equipment suggested in (b)(i)

[2]

1.3. Potassium chloride is a mineral found in many foods.

A student wants to make a salt called potassium chloride, KCl , by neutralisation of an acid by an alkali.

Describe how to make a pure, dry sample of potassium chloride in a laboratory by neutralisation.