Question

In the electrolytic cell, flow of electrons is from:
(A) Cathode to anode in solution
(B) Cathode to anode through external supply
(C) Cathode to anode through internal supply
(D) anode to cathode through internal supply

Answer 1

Hint: Charges have the inherent property by which they can flow from a direction of low voltage to high voltage. And always keep in mind that the flow of electrons is in the opposite direction of flow of current.

Complete step by step solution:

In chemistry, anode and cathode are defined as,
Anode is the electrode where the oxidation reaction happens.
Cathode is the electrode where the reduction reaction happens.

In the case of an electrolytic cell, we have to apply an external potential to force-start the reaction to go in the opposite direction. So, the convention is reversed. Now, at the negative electrode a high electron potential will be formed due to the external voltage source and electrons will get "pushed out" of the electrode. As a result, reducing the oxidized species. So the negative electrode is where the reduction reaction will happen and thus it's the cathode.

Again, at the positive electrode, a low electron potential will be formed due to the external voltage source and electrons are "sucked into" the electrode. As a result, leaving behind the reduced species. Therefore, the positive electrode is where the oxidation reaction will happen and thus it's the anode.

So, the correct option is (c).

Note: As a common trick, remember the electrons flow alphabetically, from Anode to Cathode A to C. You can also define it by the type of reaction. They flow from Oxidation to Reduction, again in alphabetical order. O to R.