You spell Chlorine wrong but the process is called electrolysis
The empirical formula is obtained by calculating the mole ratios of the atoms in the elements.
The number of moles =mass/ R.A.M
For hydrogen, no. of moles=8/1=8
For oxygen, no. Of moles=64/16=4
The tabular solution is attached.
No, It can't be chemical because it has something to do with being mechanical, an example of a chemical change would be some thing like metal rusting or wood turning to ash after being burned.