Chemical Reactions and Properties

The video tutorial explains the reaction of zinc with dilute sulphuric acid, highlighting the differences between physical and chemical changes. It provides a step-by-step procedure for conducting the experiment, including the materials required and the observations made during the reaction. The tutorial also describes tests to confirm the presence of zinc sulphate and emphasizes safety precautions.

What is an example of a physical change?

• Corrosion

• Formation of a precipitate

• Evolution of a gas

• Melting of cheese

Which of the following is a chemical change?

• Tearing a paper

• Melting of cheese

• Formation of a precipitate

• Cutting a piece of wood

What is one of the materials required for the experiment?

• Zinc dust

• Magnesium ribbon

• Copper dust

• Iron filings

What is the product formed when zinc reacts with dilute sulphuric acid?

• Zinc oxide and water

• Zinc nitrate and oxygen gas

• Zinc chloride and hydrogen gas

• Zinc sulphate and hydrogen gas

What is the nature of the hydrogen gas evolved in the reaction?

• Acidic

• Basic

• Amphoteric

• Neutral

What is observed when NaOH is added to the zinc sulphate solution?

• A white gelatinous precipitate forms

• No reaction occurs

• A blue precipitate forms

• A red precipitate forms

What happens when excess NaOH is added to the white precipitate of zinc hydroxide?

• The precipitate turns red

• The precipitate dissolves

• The precipitate turns blue

• The precipitate remains unchanged

What gas is evolved when dilute HCl is added to ferrous sulphide?

• Hydrogen gas

• Oxygen gas

• Hydrogen sulphide gas

• Carbon dioxide gas

What is formed when hydrogen sulphide gas reacts with zinc sulphate solution?

• Zinc chloride

• Zinc oxide

• Zinc sulphide

• Zinc nitrate

What precaution should be taken while handling the boiling tube?

• Keep it close to your face

• Keep it away from your face and classmates

• Shake it vigorously

• Heat it directly over a flame