English Medium Class 10 - CBSE Question Bank Solutions for Science

What is an oxidation reaction? Identify in the following reaction (i) the substance oxidised, and (ii) the substance reduced:

ZnO + C → Zn + CO

In the following reaction between lead sulphide and hydrogen peroxide:

PbS (s) + 4H₂O₂(aq) → PbSO₄(s) + 4H₂O(1)

(a) which substance is reduced?
(b) Which substance is oxidised?

Identify the component oxidised in the following reaction:

H₂S + Cl₂ → S + 2HCl

When SO₂ gas is passed through saturated solution of H₂S, the following reaction occurs:

SO₂ + 2H₂S → 2H₂O + 3S

In this reaction, which substance is oxidised and which one is reduced?

Fill in the following blanks with suitable words:

The addition of oxygen to a substance is called ......... whereas removal of oxygen is called ........

Fill in the following blanks with suitable words:

The addition of hydrogen to a substance is called ........ whereas removal of hydrogen is called .......

When a magnesium ribbon burns in air with a dazzling flame and forms a white ash, is magnesium oxidised or reduced? Why?

In the reaction represented by the equation:

MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂

(i) name the substance oxidised.
(ii) name the oxidising agent.
(iii) name the substance reduced.
(iv) name the reducing agent.

Give an example of an oxidation reaction.

Is oxidation an exothermic or an endothermic reaction?

Give one example of an oxidation-reduction reaction which is also a combination reaction.

Give one example of an oxidation-reduction reaction which is also a displacement reaction.

Explain oxidation in terms of gain or loss of oxygen with one example.

Explain reduction in terms of gain or loss of oxygen with one example.

When copper powder is heated strongly in air, it forms copper oxide. Write a balanced chemical equation for this reaction. Name (i) substance oxidised, and (ii) substance reduced.

Define oxidation in terms of gain or loss of hydrogen with one example.

Define reduction in terms of gain or loss of hydrogen with one example.

When a magnesium ribbon is heated, it burns in air to form magnesium oxide. Write a balanced chemical equation for this reaction. Name (i) substance oxidised, and (ii) substance reduced.

In the reaction represented by the following equation: 

CuO (s) + H₂ (g) → Cu (s) + H₂O (1)

(a) name the substance oxidised
(b) name the substance reduced
(c) name the oxidising agent
(d) name the reducing agent

In the context of redox reactions, the removal of hydrogen from a substance is known as:
(a) oxidation
(b) dehydration
(c) reduction
(d) dehydrogenation