The role of copper diaphragm in Whytlaw-Gray's method is
The role of copper diaphragm in Whytlaw-Gray's method is
preventing the corrosion of electrolytic cell
preventing the mixing of $\mathrm{H}_2$ and $\mathrm{F}_2$
as anode
as cathode
Solution
In Whytlaw-Gray's method for preparation of fluorine, the copper diaphragm is used to prevent the mixing of $\mathrm{H}_2$ and $\mathrm{F}_2$ liberated at cathode and anode respectively.
Reactions in the electrolytic cell