Oxidation and Reduction

Q.

The formation of copper oxide from copper in the presence of oxygen is an ____________ reaction.

$2Cu+O_2\to 2CuO$

1. Reduction

2. Decompositon

3. Oxidation

4. Displacement

Q.

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

Q.

The oxidation state of copper in $CuS{O}_4$ is -2.

1. True

2. False

Q.

In the reaction $\mathrm{PbO}+\mathrm{C}\to \mathrm{Pb}+\mathrm{CO}$

1. $\mathrm{PbO}$ is oxidized.

2. $\mathrm{C}$ acts as oxidizing agent.

3. $\mathrm{C}$ acts as reducing agent.

4. This reaction does not represent redox reaction.

Q.

In terms of electron transfer, define
(a) Oxidation
(b) Reduction

Q.

Uses of decomposition reaction.

Q.

The reaction, $H_2+C{l}_2\to 2HCl$ is

1. decomposition reaction

2. displacement reaction

3. a combination reaction

4. an isomerization reaction

Q.

$\mathrm{Zn}+\left(\mathrm{dil}.\right){\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{ZnSO}}_4+{\mathrm{H}}_2$

Above reaction is

1. decomposition reaction

2. single displacement reaction

3. oxidation reaction

4. neutralisation reaction

Q.

Explain the redox reaction with suitable example

Q.

What are the products formed when ammonia is oxidized with copper oxide?

Q.

In a mildly alkaline medium, the thiosulphate ion is oxidised by ${\mathrm{MnO}}_4^{-}$ to "A". The oxidation state of sulphur in "A" is ________.

Q.

Ammonia is a strong _______ (oxidizing/reducing) agent.

Q. The reducing agent in the following reaction is:
Pb(s) + Cu²⁺(aq) → Pb²⁺ (aq) + Cu(s)

1. Pb²⁺ (aq)
2. Cu²⁺ (aq)
3. Pb (s)
4. Cu (s)

Q.

Identify the reducing agent and oxidizing agent in the following reactions:

$3\mathrm{Fe}+4{\mathrm{H}}_2\mathrm{O}\to {\mathrm{Fe}}_3{\mathrm{O}}_4+4{\mathrm{H}}_2$

Q.

Why is gaining electrons called reduction?

Q.

Which of the following is an oxidising agent in $2Mg+O_2\left(g\right)\to 2MgO\left(s\right)$

1. $O_2$

2. Both Mg and O

3. None of these

4. Mg

Q.

Reduction is a process in which

Q.

Oxidation can involve

1. Addition of oxygen

2. Removal of Hydrogen

3. Removal of electropositive element

4. Addition of electronegative element

Q.

Calcium reacts with cold water and forms Calcium hydroxide and Hydrogen gas.

1. True
2. False

Q. What is redox reaction in simple way ??

Q.

In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of _____

1. Chlorine

2. hydrogen

3. nitrogen

4. oxygen

Q.

Why if a substance loses hydrogen is said to be oxidised and if gains Hydrogen then reduced?

Q. The potential difference between electrode and electrolyte is called ___

Q.

Electric current is passed through an aqueous solution of lithium bromide. What is the product at the cathode and anode respectively?

1. Cathode - bromine, Anode- lithium
2. Cathode - Lithium, Anode- lithium
3. Cathode - bromine, Anode- bromine
4. Cathode - Lithium, Anode - bromine

Q.

Electrolysis is also a redox reaction.

1. True

2. False

Q.

How will you distinguish between lead nitrate and zinc nitrate solution with the help of ammonium hydroxide solution? Explain with equation.

Q.

What is the oxidizing agent in the following redox reaction?

$Zn\left(s\right)+C{u}^{2+}\left(aq\right)\to Z{n}^{2+}\left(aq\right)+Cu\left(s\right)$

1. Cu²⁺

2. Zn²⁺

3. Zn

4. Cu

Q.

A student took quicklime in a china dish and added a small amount of water to it. He would hear

1. A pop sound

2. A crackling sound

3. A hissing sound

4. No sound at all

Q.

Describe the role played by graphite in the extraction of aluminium.

Q.

Reduction involves

1. Addition of Hydrogen

2. Addition of any electropositive element

3. Removal of oxygen

4. Removal of any electronegative element