CBSE Class 10 Science Sample Paper 01 (2020-2021)

 Translate the following statements into chemical equations and then balance them.

  Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

• 2K + 2H₂O → 2KOH + H₂

• 3BaCl₂ + Al₂(SO₄)₃ → 2AlCl₃ + 3BaSO₄

• 2H₂S + 3O₂ → 2H₂O + 2SO₂

• 3H₂ + N₂ → 2NH₃

 Translate the following statements into chemical equations and then balance them.

  Hydrogen sulphide gas burns in air to give water and sulphur dioxide

• 2K + 2H₂O → 2KOH + H₂

• 3BaCl₂ + Al₂(SO₄)₃ → 2AlCl₃ + 3BaSO₄

• 2H₂S + 3O₂ → 2H₂O + 2SO₂

• 3H₂ + N₂ → 2NH₃

 Translate the following statements into chemical equations and then balance them.

  Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.

• 2K + 2H₂O → 2KOH + H₂

• 3BaCl₂ + Al₂(SO₄)₃ → 2AlCl₃ + 3BaSO₄

• 2H₂S + 3O₂ → 2H₂O + 2SO₂

• 3H₂ + N₂ → 2NH₃

 Translate the following statements into chemical equations and then balance them.

  Methane burns in oxygen to form CO2 and water. Write a balanced equation for the reaction

• 2K + 2H₂O → 2KOH + H₂

• 3BaCl₂ + Al₂(SO₄)₃ → 2AlCl₃ + 3BaSO₄

• 2H₂S + 3O₂ → 2H₂O + 2SO₂

• CH4+2O2→CO2+2H2O.

Identify the reducing agent in the following reactions

4NH3 + 5O2 → 4NO + 6H2O

• Ammonia (NH₃) is the reducing agent, it has reduced O₂ which acts as an oxidising agent.

• Water (H₂O) is the reducing agent. It has reducedF₂ which acts as an oxidising agent.

• Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe₂O₃) which acts as an oxidising agent.

• Hydrogen (H₂) is the reducing agent, it has reduced oxygen (O₂) which acts as an oxidising agent.

Identify the reducing agent in the following reactions

H2O + F2 → HF + HOF

• Ammonia (NH₃) is the reducing agent, it has reduced O₂ which acts as an oxidising agent.

• Water (H₂O) is the reducing agent. It has reducedF₂ which acts as an oxidising agent.

• Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe₂O₃) which acts as an oxidising agent.

• Hydrogen (H₂) is the reducing agent, it has reduced oxygen (O₂) which acts as an oxidising agent.

Identify the reducing agent in the following reactions

Fe2O3 + 3CO → 2Fe + 3CO2

• Ammonia (NH₃) is the reducing agent, it has reduced O₂ which acts as an oxidising agent.

• Water (H₂O) is the reducing agent. It has reducedF₂ which acts as an oxidising agent.

• Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe₂O₃) which acts as an oxidising agent.

• Hydrogen (H₂) is the reducing agent, it has reduced oxygen (O₂) which acts as an oxidising agent.

Identify the reducing agent in the following reactions

2H2 + O2 → 2H2O

• Ammonia (NH₃) is the reducing agent, it has reduced O₂ which acts as an oxidising agent.

• Water (H₂O) is the reducing agent. It has reducedF₂ which acts as an oxidising agent.

• Carbon monoxide (CO) is the reducing agent, it has reduced ferric oxide (Fe₂O₃) which acts as an oxidising agent.

• Hydrogen (H₂) is the reducing agent, it has reduced oxygen (O₂) which acts as an oxidising agent.

The structural formula of Ethyne

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Define 'refractive index of a transparent medium'. What is its unit? Which one has a higher refractive index, glass or water? What is the first statement of the audio clip?

• Refractive index of transparent medium is defined as the ratio of speed of light in vacuum to the speed of light through medium.

• That is, Refractive index, n=c/v. Where, Speed of light = c Speed of light in medium = v

• It has no unit because it is a ratio of two quantities of same type (speed).

• Glass has higher refractive index (1.52) than water, because refractive index of water is 1.33.