Applications of Electrolysis and Electrolytic Cell

Q.

The metal which does not react with cold as well as hot water but, reacts with steam is

1. sodium

2. potassium

3. magnesium

4. iron

Q.

Why cathode is connected to the negative terminal instead of being positive?

Q.

What happens when zinc reacts with water?

Q.

How many electrons are transferred during following change $2{\mathrm{I}}^{-}\left(\mathrm{aq}\right)\to {\mathrm{I}}_2\left(\mathrm{s}\right)$?

Q.

Which of the following metals do not react with sulphuric acid under any condition?

1. Zinc

2. Copper

3. Gold

4. Platinum

Q.

What is the difference between electrowinning and electrorefining?

Q.

Arrange the following according to the instructions: $\mathrm{K},\mathrm{Pb},\mathrm{Ca},\mathrm{Zn}$ (In the increasing order of the reactivity).

Q. Which of the following occurs in a $Cu-Zn$ cell?

1. Oxidation occurs at the copper cathode

2. Chemical energy is converted to light energy

3. Reduction occurs at the copper cathode

4. Reduction occurs at the anode

Q.

Compare in tabular form the reactivities of the following metals with cold and hot water:

(a) Sodium (b) Calcium (c) Magnesium

Q.

Iron displaces copper from its salt solution because:

1. Both Fe and Cu are equally reactive

2. Fe is less reactive than Cu

3. Fe is more reactive than Cu

4. None of the above

Q.

The metals that will not displace hydrogen on reaction with dilute acids are

1. Copper

2. Silver

3. Gold

4. Zinc

Q.

Write the physical and chemical properties of oxygen and nitrogen.

Q. Give three applications of electrolysis.

Q.

Copper has the ability to displace nickel from its salt.

1. True

2. False

Q.

Why sodium is kept in kerosene not in petrol or diseal?

Q.

What is the value of $e.m.f.$ a voltaic cell?

Q. List out the main applications of electrolysis.

Q.

Which of the following options are showing an oxidation reaction?

1. $Mg\left(s\right)\to M{g}^{2+}+2e^{-}$

2. $Mg\left(s\right)+2e^{-}\to M{g}^{2+}$

3. $Zn\left(s\right)\to Z{n}^{2+}+2e^{-}$

4. $Zn\left(s\right)+2e^{-}\to Z{n}^{2+}$

Q.

Read the given statements and choose the correct option

i) Electrolytic cell is a device which converts electrical energy into a chemical energy by a process of electrolysis.

ii) Electrochemical cell is a device which converts a chemical energy into electrical energy through a redox reaction.

1. Neither of (i) and (ii) are correct

2. Only (i) is correct
3. Only (ii) is correct
4. Both (i) and (ii) are correct

Q.

6.Which of the following methods is not used for the prevention of corrosion?

1. greasing

2. painting

3. plating

4. heating

Q.

Which of the following statements about electrochemical series is wrong?

1. Metals place above hydrogen are least reactive.

2. It does not compare the relative reactivity of metals.

3. It compares relative strengths of oxidizing agents.

4. Hydrogen is centrally placed element.

Q. Question 8
In the electrolytic refining of a metal M, what would you take as the anode, the cathode and the electrolyte?

Q.

Write an equation for the following reaction:

(d) Iron reacts with steam

Q.

Copper is less reactive than tin.

1. True
2. False

Q.

When magnesium metal reacts with sulphuric acid it forms magnesium sulphate along with the evolution of hydrogen gas.

$Mg+H_{2}S{O}_4$$\to$$MgS{O}_4$+$H_2$

For experimental studies the conditions of the reaction was modified and rate of reaction was monitored. In which of the following case the occurance of the reaction is fastest?

1. Mg + H₂SO₄ → MgSO₄ + H₂ at 36^oC.

2. Mg + H₂SO₄ → MgSO₄ + H₂ at 16^oC.

3. Mg + H₂SO₄ → MgSO₄ + H₂ at 26^oC.

4. Mg + H₂SO₄ → MgSO₄ + H₂ at 0^oC.

Q.

To protect objects from corrosion, which of the following process can be done

1. None of the above

2. Electrolytic decomposition

3. Electrorefining

4. Electroplating

Q.

Rohit has an impure copper plate and wants to purify it by electroplating. Using an electrolytic setup, he can do this by

1. using the impure copper plate as the positive terminal electrode.
2. using impure copper plate as the negative terminal electrode.
3. breaking the impure copper plate into 2 halves and using them as electrodes.
4. simply placing the impure copper plate in the electrolyte.

Q. Which among the following statements is incorrect for magnesium metal?

(a) It burns in oxygen with a dazzling white flame.
(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas.
(c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas.
(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas.

Q.

Give an example of a reaction which represents reduction.

Q. Question 5
Which of the following oxide(s) of iron would be obtained on a prolonged reaction of iron with steam?

(a) $\text{FeO}$
(b) ${\text{Fe}}_2{\text{O}}_3$
(c) ${\text{Fe}}_3{\text{O}}_4$
(d) ${\text{Fe}}_2{\text{O}}_3$ and ${\text{Fe}}_3{\text{O}}_4$