English Medium Class 10 - CBSE Question Bank Solutions

State an important use of decomposition reactions.

Give one example of a decomposition reaction which is carried out by applying heat.

Give one example of a decomposition reaction which is carried out with electricity.

What type of chemical reaction is used to extract metals from their naturally occurring compounds like oxides or chlorides?

What type of reaction is represented by the following equation?

\[\ce{CaCO3 -> CaO + CO2}\]

What type of reaction is represented by the following equation?

\[\ce{2FeSO4 -> Fe2O3 + SO2 + SO3}\]

What type of reaction is represented by the following equation?

\[\ce{NH4Cl -> NH3 + HCl}\]

What type of chemical reaction takes place when limestone is heated?

What type of chemical reaction takes place when silver bromide is exposed to sunlight?

What type of chemical reaction takes place when electricity is passed through water?

What type of chemical reaction is represented by the following equation?

\[\ce{X -> Y + Z}\]

What type of reaction is represented by the following equation?

\[\ce{NH4NO2 -> N2 + 2H2O}\]

What is the colour of ferrous sulphate crystals? How does this colour change after heating?

Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?

What is meant by a decomposition reaction?

State the change in colour observed in the following case, mentioning the reason:

Silver chloride is exposed to sunlight.

Which of the following can be decomposed by the action of light?

When a green iron salt is heated strongly, its colour finally changes to brown and odour of burning sulphur is given out.

1. Name the iron salt.
2. Name the type of reaction that takes place during the heating of iron salt.
3. Write a chemical equation for the reaction involved.

Two metals X and Y form the salts XSO₄ and Y₂SO₄, respectively. The solution of salt XSO₄ is blue in colour whereas that of Y₂SO₄ is colourless. When barium chloride solution is added to XSO₄ solution, then a white precipitate Z is formed along with a salt which turns the solution green. And when barium chloride solution is added to Y₂SO₄ solution, then the same white precipitate Z is formed along with colourless common salt solution.

1. What could the metals X and Y be?
2. Write the name and formula of salt XSO₄.
3. Write the name and formula of salt Y₂SO₄.
4. What is the name and formula of white precipitate Z?
5. Write the name and formula of the salt which turns the solution green in the first case.

A metal salt MX when exposed to light splits up to form metal M and a gas X₂. Metal M is used in making ornaments whereas gas X₂ is used in making bleaching powder. The salt MX is itself used in black and white photography.

1. What do you think metal M is?
2. What could be gas X₂?
3. Name the metal salt MX.
4. Name any two salt solutions which on mixing together can produce a precipitate of salt MX.
5. What type of chemical reaction takes place when salt MX is exposed to light? Write the equation of the reaction.