When you add about 2 ml of acetic acid to a test tube containing an equal amount of distilled water and leave the test tube to settle after shaking its contents, what will you observe in the test tube after about 5 minutes?

• A white precipitate settling at its bottom

• A clear colorless solution

• A layer of water over the layer of acetic acid.

• A layer of acetic acid over the layer of water.

You are given the following solutions:

Hydrochloric acid (HCl), sulphuric acid (H₂SO₄), nitric acid (HNO₃), acetic acid (CH₃COOH), sodium hydroxide (NaOH), calcium hydroxide [(Ca(OH)₂], potassium hydroxide (KOH), magnesium hydroxide [Mg(OH)₂] and ammonium hydroxide (NH₄OH). Give the colour change for each of these solutions with red litmus, blue litmus, phenolphthalein and methyl orange solutions.

Choose the olfactory indicators and give their characteristics: red cabbage extract, onion, vanilla extract, litmus, clove oil.

Take 5 ml hydrochloric acid in a boiling tube or a conical flask. Add a few pieces of zinc granules to it.

(a) What do you observe on the surface of zinc granules?
(b) Name the gas evolved.
(c) What happens when the above gas is passed through soap solution?
(d) What happens when a burning candle is brought near the gas filled tube?