what we call the ion which moves towards the cathode

 

 

Dear student 

Let us understand this by the help of examples.

Electrolysis of a concentrated aqueous solution of sodium chloride produces chlorine gas at the anode, hydrogen gas at the cathode and the concentration of NaOH in the electrolyte increases.
However, if a dilute solution of sodium chloride is electrolysed, oxygen gas instead of chlorine gas is evolved at the anode and concentration of NaCl in the electrolyte increases. The electrolyte does not become alkaline. 
Hydrogen gas is released at the cathode in both cases.
Therefore, concentration of NaCl influences the products formed.