Redox Reactions

Q. gas is filled in a packet of chips to prevent .

1. Oxygen
2. Nitrogen
3. rancidity
4. corrosion

Q.

What causes rancidity? Name an antioxidant that prevents rancidity.

Q.

Nitrogen gas is used in chips packets because it controls the Oxygen reactivity.

1. The agents called antioxidants prevent oxidation of oils and fats in food.

2. Nitrogen is used to flush bags of chips beacuse it slows down the oxidation of chips.

Q.

In the reaction $3Mn{O}_2\left(s\right)+4Al\left(s\right)\to 3Mn\left(s\right)+2A{l}_2{O}_3\left(s\right)$ the oxidising agent is

1. $Mn{O}_2$

2. $Al$

3. $A{l}_2{O}_3$

4. $Mn$

Q. In which of the following, heat energy will be evolved?

1. Burning of L.P.G.
2. Dissolution of $N{H}_{4}Cl$ in water
3. Electrolysis of water
4. Decomposition of AgBr in the presence of sunlight

Q.

The fats and oils present in food are oxidized resulting to the spoilage of food. This phenomenon is called ________.

1. Basicity

2. Alkalinity

3. Acidity

4. Rancidity

Q. Water is decomposed into water and hydrogen by means of an electric current by the method of____________

1. Electrolysis
2. Electroplating
3. Electric heating
4. None of the above

Q.

In the reaction $3Mn{O}_2+4Al\to 3Mn+2A{l}_2{O}_3$ , the oxidising agent is :

1. $Mn{O}_2$

2. $Al$

3. $A{l}_2{O}_3$

4. $Mn$

Q.

For the reaction $CuO+H_2\to Cu+H_{2}O$
Which of the following statement is correct?

1. CuO is being oxidised and hydrogen is being reduced
2. CuO is being reduced and hydrogen is being oxidised
3. Both CuO and $H_2$ are being oxidised
4. Both CuO and $H_2$ are being reduced

Q.

Unpleasant taste and foul smell in fatty food are caused due to ____. (dehydration / rancidity).

Q.

Which of the given statements are correct about the reaction mentioned below?
$2PbO\left(s\right)+C\left(s\right)\to 2Pb\left(s\right)+C{O}_2\left(g\right)$
i) Lead is getting reduced
ii) Carbon dioxide is getting oxidised
iii) Carbon is getting oxidised
iv) Lead oxide is getting reduced

1. (iii) and (iv)

2. (i) and (iii)

3. (i), (ii) and (iii)

4. (i) and (ii)

Q.

Which catalyst is used in bosch process when water gas is mixed with excess steam?

1. $F{e}_3{O}_4$

2. $C{r}_2{O}_3$

3. $F{e}_2{O}_3$

4. $K_{2}C{O}_3$

Q. For the reaction $CuO+H_2\to Cu+H_{2}O$
Which of the following statement is correct?

1. $CuO$ is being reduced and hydrogen is being oxidised
2. Both $CuO$ and $H_2$ are being reduced
3. $CuO$ is being oxidised and hydrogen is being reduced
4. Both $CuO$ and $H_2$ are being oxidised

Q.

Differentiate between exothermic and endothermic reactions.

Q. Water is decomposed into water and hydrogen by means of an electric current by the method of____________

1. Electrolysis
2. Electric heating
3. None of the above
4. Electroplating

Q.

Determine which substance is oxidized and which substance is reduced in the following reactions:
$C{O}_2\left(g\right)+H_2\left(g\right)\to CO\left(g\right)+H_{2}O\left(g\right)$

1. $C{O}_2$ is reduced, $H_2$ is oxidized

2. Both $C{O}_2\&H_2$ are reduced

3. Both $C{O}_2\&H_2$ are oxidized

4. $C{O}_2$ is oxidized, $H_2$ is reduced

Q. Layer of gets deposited over aluminium rod in anodising process.

1. aluminum oxide
2. platinum oxide
3. carbon monoxide
4. aluminium hydroxide

Q. Which among the following statement(s) is(are) correct for the given redox reaction:
$P{b}_3{O}_4+8HCl\stackrel{Heat}{\to }3PbC{l}_2+C{l}_2+4H_{2}O$
I. $HCl$ is oxidised
II. $HCl$ is reduced
III. $P{b}_3{O}_4$ is reduced
IV. $P{b}_3{O}_4$ is oxidised

1. II & IV
2. I only
3. I & III
4. II only

Q.

A chemical reaction in which the oxidation states of atoms are changed is known as a ___ reaction.

Q.

Which of the following statements is incorrect?

1. In oxidation, oxygen in added to a substance.

2. In reduction, hydrogen is added to a substance.

3. The oxidising agent is oxidised.

4. The reducing agent is oxidised.

Q. Which among the following reacts with steam?

1. Fe
2. Pt
3. Au
4. Ag

Q. Lead nitrate on thermal decomposition produces

1. Lead oxide
2. Sulphur dioxide
3. carbon monoxide
4. Carbon dioxide

Q. Which of the following provides energy for decomposition during electrolysis?

1. Chemical
2. Heat
3. Light
4. Electricity

Q. Which of these is not a kind of chemical reaction?

1. Displacement
2. Combination
3. Conduction
4. Decomposition

Q. Decomposition of water into hydrogen and oxygen involves absorption of energy.

1. \N
2. \N

Q. A salt contains cation $A^{2+}$ and anion $B^{2-}$. Both decolourise ${MnO}_4^{-}$ is acidic medium. Salt is :

1. ferrous oxalate
2. None of these
3. both (a) and (b)
4. ferric oxalate

Q. Which of the following provides energy for decomposition during electrolysis?

1. Heat
2. Chemical
3. Light
4. Electricity

Q. Reaction of $PbO$ and Carbon
$PbO+C\to Pb+CO$

1. here carbon is reducing agent
2. here $Pb$ is oxidizing agent
3. Both a & b
4. None of the above

Q. In which of the following, heat energy will be evolved?

1. Burning of L.P.G.
2. Dissolution of $N{H}_{4}Cl$ in water
3. Decomposition of AgBr in the presence of sunlight
4. Electrolysis of water