The photoelectric current from Na (work function ) is stopped by the output voltage of the cell . The pH of aq. HCl required to stop the photoelectric current from K (), all other conditions remaining

Question

The photoelectric current from Na (work function ) is stopped by the output voltage of the cell . The pH of aq. HCl required to stop the photoelectric current from K (), all other conditions remaining the same, is  (to the nearest integer). Given: ;

Canvas Classes · Accepted Answer

Strategy:
 This combined problem relates Einstein's Photoelectric Equation to Electrochemical Cell potential. The "stopping voltage" from the cell must equal the maximum kinetic energy () of the emitted electrons.

Step 1: Na Electrode Data
Work function .
Stopping voltage () provided by the cell at .
The cell is .

Using given value relation .
.

Step 2: K Electrode Data
.
Required stopping voltage .

Step 3: Find pH for required

Given answer  suggesting a specific rounded .

More questions from Electrochemistry