I have some basic doubts.
When we dissolve some salts in water, are they separating as ions and do they exist as independent ions?
In the case of CuCl2 dissolved in water is it forming Cu(2+) and 2Cl(1-) and exist as independent Cu(2+) and Cl(-)?

If so, will that Cl(1-) react with hydrogen in water to form HCl?
Because, before adding CuCl2 water is showing pH~7 and after adding 0.1M of CuCl2 it turned to pH~4.5

Can we use this change in pH as a comparative measure to calculate number of Cu(2+) ions in a fixed amount of the solvent?