Tag: metallic and electrolytic conduction

Questions Related to metallic and electrolytic conduction

Which one of the following solution will conduct electricity?

  1. Sugar in water

  2. Sugar in ethyl alcohol

  3. Iodine in ethyl alcohol

  4. Magnesium chloride water


Correct Option: D
Explanation:

Solution which contains free ions conducts electricity.

Since, Magnesium Chloride aqueous solution will have Mg ions. Hence, it will conduct electricity

A solution of sodium in liquid ammonia at $-33^oC$ conducts electricity. On cooling, the conductivity of this solution _______.

  1. decreases

  2. increases

  3. remains same

  4. becomes 0


Correct Option: A
Explanation:

A solution of sodium in liquid ammonia at $-33^oC$ conducts electricity. On cooling, the conductivity of this solution ...... The conductivity of the solution is due to presence of ammoniated electrons. With decrease in the temperature, the mobility of ammoniated electrons decreases due to which the electrical conductivity decreases.

An aluminium wire is:

  1. non-electrolyte

  2. weak electrolyte

  3. metallic conductor

  4. none of these


Correct Option: C
Explanation:

Aluminium is metal so its wire will act as metallic conductor and it conducts electricity due to valence shell electrons.

Examine the following statement sand select the correct option.
A : Electrolytic conduction is a physical change.
B : In Electrolytic conduction, positive as well as negative ions conduct electricity.

  1. Both A and B are true

  2. Both A and B are false

  3. A is true and B is false

  4. A is false but B is true


Correct Option: D
Explanation:

Electrolytic conduction is a chemical change. It involves a redox reaction.
In electrolytic conduction, positive as well as negative ions conduct electricity.
For example, during electrolysis of molten NaCl, both $Na^+$ and $Cl^-$ ions are involved in the conduction of electricity.
Thus, A is false but B is true.

Assertion: In electrolysis of water, ions are not discharged at electrodes.
Reason: The current-carrying ions in an electrolytic cell are not necessarily discharged at the electrodes.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

  2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: A
Explanation:

The current-carrying ions in an electrolytic cell are not necessarily discharged at the electrodes. This is true for the electrolysis of aqueous salt solutions in which water is involved in the electrode reactions and not the current carrying ions.
$2H _2O \rightarrow O _2 + 4H^+ +4e^-$    oxidation
$2H _2O + 2e^- \rightarrow H _2 +2OH^-$   reduction

Assertion: Electrolytic conductance increases with the increase of temperature
Reason: Metallic conductance decreases with the increase in temperature.

Choose the correct option.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

  2. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: B
Explanation:

The conductivity of an electrolyte depends on the temperature. With an increase in temperature, the conductivity of an electrolyte increases.This is due to increase in ionic mobility. 


For metals, the thermal conductivity is mainly a function of the motion of free electrons. As the temperature increases, the molecular vibrations increase (in turn increasing the mean free path of molecules). So, they obstruct the flow of free electrons, thus reducing the conductivity.

Which of the following will conduct electricity?

  1. Ammonium acetate

  2. Ammonium hydroxide

  3. Sodium hydroxide

  4. formic acid


Correct Option: A,C
Explanation:

Ammonium acetate is a salt. Salts conduct electricity due to complete dissociation. Ammonium hydroxide is a weak base and does not conduct electricity. Sodium hydroxide is a strong base and conducts electricity. Formic acid is a weak acid and does not conduct electricity. 

An electrolytic cell was set up. Dilute $HCl$ is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow brightly

  2. not glow

  3. depends on amount of HCl

  4. none of the above


Correct Option: A
Explanation:

$HCl$ is a strong acid and it has ions to carry the current. So the circuit will be completed and the bulb will glow brightly.

Which of the following is a poor conductor of electricity?

  1. $NH _4OH$

  2. $HCl$

  3. $CH _3COOH$

  4. $NaOH$


Correct Option: A,C
Explanation:

Ammonium hydroxide and acetic acid are weak bases and acid respectively. Hence, they are poor conductors. 

In which of the following cases, conductivity decreases with an increase in temperature?

  1. Fused $NaCl$

  2. $Cd$

  3. $NaOH$

  4. ${NH} _{4}OH$


Correct Option: B
Explanation:

The electrical conductivity of a conductor will decrease with an increase in temperature. But for acids bases and salts raising the temperature gives more energy to the ions making them move faster, and hence increasing the conductivity.