158. During measurement of electrode potential of half - cell
coupled with S.H.E, bubbles were formed in the
interior of solution of S.H.E. It shows that S.H.E act as:
(a) Anode
(b) Cathode
(c) Anyone
(d) Can't be predicted
Answers
Answer:
b.Cathode
Explanation:
Prerequisite knowledge:
SHE :
It consists of platinum wire sealed in a glass tube and has a platinum foil attached to it.The foil is coated with finely divided platinum and acts as platinum electrode.It is dipped into acid solution containing H⁺ ions in 1M concentration.
Pure hydrogen gas at 1 atm is constantly bubbled into the solution at constant temperature of 25° C or 298 K.
The following reactions occur depending on whether it acts as a cathode or anode.
1. At anode:
H₂ (g)-----------> 2 H⁺ + 2 e⁻ (equation 1)
2. At cathode
2 H⁺ + 2 e⁻-----------> H² (g) (equation 2)
Approach to the question:
- According to our question we find that some bubbles are formed at SHE.
- This is only possible if some gaseous products are obtained.
- From the above two equations, only equation 2 gives a gaseous product ie H₂.
- Hence we can say that according to the equation the SHE should act as cathode.
Therefore we can say that SHE acts as Cathode.
Hope this helps.
Answer:
option B is the correct answer