Question

Name the substance oxidised and substance reduced in the following reactions: (a) MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O (b) 2H2S + SO2 → 2H2O + 3S (c) 2PbO + C → 2Pb + CO2 (d) PbS + 4H2O2 → PbSO4 + 4H2O (e) CuO + H2 Heat → Cu + H2O

Answer 1

The answer is redox solution

Answer 2

Explanation:

To Do :-

• Name the substance oxidised and reduced.

Solution :-

As we know that :-

• Addition of oxygen is called oxidation.
• Removal of oxygen is called reduction.
• Addition of hydrogen is called reduction.
• Removal of hydrogen is called oxidation.

a)

MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O

Here, MnO2 is losing oxygen to form MnCl2, So MnO2 is being reduced to MnCl2.

On other hand, HCl is losing hydrogen to form Cl2, so HCl is being oxidised to Cl2.

Hence,

Substance reduced : MnO2

Substance oxidised : HCl

b)

2H2S + SO2 → 2H2O + 3S

Here, SO2 is losing oxygen to form S, So SO2 is being reduced to S.

On other hand, H2S is losing hydrogen to form S. So H2S is being oxidised to S.

Hence,

Substance reduced : SO2

Substance oxidised : H2S

c)

2PbO + C → 2Pb + CO2

Here, PbO is losing oxygen to form Pb. So PbO is being reduced to Pb.

On other hand, Carbon is gaining Oxygen to form CO2. So C is being oxidised to CO2.

Hence,

Substance reduced : PbO

Substance oxidised : C

d)

PbS + 4H2O2 → PbSO4 + 4H2O

Here, PbS is gaining oxygen to form PbSO4. So PbS is being oxidised to PbSO4.

On other hand, H2O2 is losing oxygen to form H2O. So H2O2 is being reduced to H2O.

Hence,

Substance reduced : H2O2

Substance oxidised : PbS

e)

CuO + H2 → Cu + H2O

Here, CuO is losing oxygen to form Cu. So CuO is being reduced to Cu.

On other hand, H2 is gaining oxygen to form H2O. So H2 is being oxidised to H2O

Hence,

Substance reduced : CuO

Substance oxidised : H2