In the isolation of fluorine a number of difficulties were encountered. Which statements are incorrect?

1. Fluorine reacts with water and glass vessels.
Thus, option A is incorrect.

2. Fluorine has great affinity for hydrogen. It reacts with hydrogen with an explosion even in dark.
However, this was not the difficulty encountered in the extraction of fluorine.
Thus, option B is incorrect.

3. The electrolysis of aqueous HF gives oxygen and not ozonized oxygen.
Thus, option C is also incorrect.

4. The potential required for the discharge of the fluoride ions is lowest.
Thus, option D is also correct.