Redox Reactions

Q.

What happens when silver nitrate is mixed with the solution of sodium chloride?

Q.

Sodium bromide is added to an aqueous solution of a metal nitrate $\mathrm{A}$. A yellow precipitate $\mathbf{B}$ is obtained which is used in photography. Compound $\mathbf{B}$ is photosensitive and decomposes to its constituents on exposure to sunlight, accompanied by the evolution of a reddish- brown gas. Write down the balanced equation and identify $\mathrm{A}$ and $\mathbf{B}$.

Q.

What happens when zinc carbonate is heated? (write balanced chemical equation)

Q.

State what will you observe when lead nitrate crystals are heated in a dry test tube.

Q.

Complete the following equation:$$$\mathrm{Al}{\left(\mathrm{OH}\right)}_2+\mathrm{NaOH}\left(\mathrm{aq}\right)\to$

Q.

In the reaction $2KCl{O}_3\underset{\Delta }{\overset{Mn{O}_2}{\to }}2KCl+3O_2$, what do the symbol $\Delta$ and MnO₂, written on the arrow signify.

Q.

When Lead nitrate is heated it decomposes with a cracking sound, a reddish brown gas is liberated and a solid residue is left in the test tube. Name the type of the reaction.

Q.

Name the following:

(d) A salt that is prepared by double decomposition.

Q.

On heating ferrous sulfate crystals, one would get:

1. sweet smell

2. rotten egg smell

3. the smell of burning sulfur

4. no solid residue

Q.

Question 54
How would you bring about the following conversions? Name the process and write the reaction involved.

(a) Ethanol to ethene

(b) Propanol to propanoic acid

Q.

Balance the following equations:

$\mathrm{Mg}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{MgSO}}_4+{\mathrm{H}}_2$

Q.

What happens when Ammonium carbonate is exposed to air? (write balanced chemical equation)

Q. Compare hydrogen and halogen on the basis of: reaction with oxygen

Q. Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?

1. $S+2H_{2}S{O}_4\to 3S{O}_2+2H_{2}O$
   
2. $Cu+2H_{2}S{O}_4\to CuS{O}_4+S{O}_2+2H_{2}O$
   
3. $C+2H_{2}S{O}_4\to C{O}_2+2S{O}_2+2H_{2}O$
   
4. $Ca{F}_2+H_{2}S{O}_4\to CaS{O}_4+2HF$

Q.

What happens when crystals of copper nitrate is heated? (write balanced chemical equation)

Q. Compare hydrogen with the alkali metals on the basis of: Oxide formation.

Q.

Which among the following statements is/are true?

Exposure of silver chloride to sunlight for a long duration turns grey due to

(i) the formation of silver by decomposition of silver chloride.

(ii) sublimation of silver chloride

(iii) release of chlorine gas from silver chloride

(iv) oxidation of silver chloride

1. (i) only

2. (i) and (iii)

3. (ii) and (iii)

4. (iv) only

Q.

Translate the following statement into chemical equations and balance:

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

Q. Question 2

The following reaction is an example of a

$4{\text{NH}}_3\text{(g)}+5{\text{O}}_2\text{(g)}\to 4\text{NO(g)}+6{\text{H}}_2\text{O(g)}$

(i) Displacement reaction
(ii) Combination reaction
(iii) Redox reaction
(iv) Neutralisation reaction

(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)

Q.

State what would you observe and write the chemical equation for the reaction that takes place when sodium hydroxide solution is added to a solution of ferric chloride.

Q.

Which one is not a chemical decomposition reaction?

1. $2{\mathrm{NaHCO}}_3\to {\mathrm{Na}}_2{\mathrm{CO}}_3+{\mathrm{H}}_2\mathrm{O}+{\mathrm{CO}}_2$

2. $\mathrm{Zn}+2\mathrm{HCl}\to {\mathrm{ZnCl}}_2+{\mathrm{H}}_2$

3. $2{\mathrm{Pb}}_3{\mathrm{O}}_4\to 6\mathrm{PbO}+{\mathrm{O}}_2$

4. ${\mathrm{CuCO}}_2\to \mathrm{CuO}+{\mathrm{CO}}_2$

Q.

Why is decomposition reaction called opposite of combination reaction? Write equations for these reactions.

Q. $3{\text{MnO}}_2\left(s\right)+4\text{Al}\left(s\right)\to 3\text{Mn}\left(s\right)+2{\text{Al}}_2{\text{O}}_3\left(s\right)$

In the above reaction, the oxidising agent is:

1. ${\text{MnO}}_2$
2. $\text{Al}$
3. ${\text{Al}}_2{\text{O}}_3$
4. $\text{Mn}$

Q. Some oils and fats give a bad smell and taste because of _________ .

1. rancidity
2. decomposition reaction
3. hydrogenation reaction
4. double displacement reaction

Q. The reaction, $H_{2}S+H_2{O}_2\to S+2H_{2}O$ manifests:

1. Acidic nature of $H_2{O}_2$
2. Oxidising action of $H_2{O}_2$
3. Reducing nature of $H_2{O}_2$
4. Alkaline nature of $H_2{O}_2$

Q.

Explain with the help of the equations, how the following salts can be prepared in the laboratory:

(e) Lead chloride

Q.

Which of the following reactions involves oxidation-reduction

1. 

2. 

3. 

4. 

Q.

The process of reduction involves -

1. The absorption of oxygen atoms

2. The absorption of electrons

3. The release of electrons

4. Neither absorption nor release of electrons

Q. Reduction of the metal centre in aqueous permaganate ion involves:

1. $3$ electrons in neutral medium
2. $5$ electrons in neutral medium
3. $3$ electrons in alkaline medium
4. $5$ electrons in acidic medium

Q.

Balance the following chemical equations and identify the type of chemical reaction:

(a) $\mathrm{Mg}\left(\mathrm{s}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to {\mathrm{MgCl}}_2\left(\mathrm{s}\right)$

(b) $\mathrm{HgO}\left(\mathrm{s}\right)\to \mathrm{Hg}\left(\mathrm{l}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$

(c) $\mathrm{Na}\left(\mathrm{s}\right)+\mathrm{S}\left(\mathrm{s}\right)\to {\mathrm{Na}}_2\mathrm{S}\left(\mathrm{s}\right)$

(d) ${\mathrm{TiCl}}_4\left(\mathrm{l}\right)+\mathrm{Mg}\left(\mathrm{s}\right)\to \mathrm{Ti}\left(\mathrm{s}\right)+{\mathrm{MgCl}}_2\left(\mathrm{s}\right)$

(e) $\mathrm{CaO}\left(\mathrm{s}\right)+{\mathrm{SiO}}_2\left(\mathrm{s}\right)\to {\mathrm{CaSiO}}_3\left(\mathrm{s}\right)$

(f) ${\mathrm{H}}_2{\mathrm{O}}_2\left(\mathrm{l}\right)\to {\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)$