Tag: electrochemistry

Quizzes (9) Questions (132)

Questions Related to electrochemistry

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry
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
Reveal answer Fill a bubble to check yourself
A Correct answer
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

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry
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
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Which of the following will conduct electricity?

  1. Ammonium acetate

  2. Ammonium hydroxide

  3. Sodium hydroxide

  4. formic acid
Reveal answer Fill a bubble to check yourself
A,C Correct answer
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. 

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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

  1. Fused $NaCl$
  2. $Cd$
  3. $NaOH$
  4. ${NH} _{4}OH$
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Which of the following solutions contains the greatest number of ions assuming that each solute is fully ionized?

  1. $1$ cm$^{-3}$ of $0.2M$ ${Na} _{2}{SO} _{4}$
  2. $1$ cm$^{-3}$ of $0.2M$ $Ca{Cl} _{2}$
  3. $1$ cm$^{-3}$ of $0.2M$ $NaCl$
  4. $1$ cm$^{-3}$ of $0.2M$ ${Cr} _{2}{({SO} _{4})} _{3}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

No. of ions in 11 molecule of $Na _2SO _4=3$ 

No. of ions in 11 molecule of $CaCl _2=3$
No. of ions in 11 molecule of $NaCl=2$
No. of ions in 11 molecule of $Cr _2(SO _4) _3=5$
As the molarity and volume is same for all the given substances, number of ions will be greatest for the compound having greatest number of ions in one molecule. Therefore, $Cr _2(SO _4) _3$ will have the greatest number of ions.