The answer is option 1 that is KCl . As here the K+ ion that is cation has lower electrode potential than H. Thus hydrogen is liberated at cathode and accumulate at one electrode and results in increase in pH.

C and d nhi hoyga kyoki isme oH ion electrode pe deposit ho jyga a and B mai OH sol mai rhegabut in option b cu deposit on electrode and H+ion is in sol it combine with OH and form waterbut in option a k+react with OH and strong base formI.e. . increase in ph

Answer:

The increased pH near one of the electrodes during electrolysis of an aqueous salt solution indicates the formation of hydroxide ions (OH-) near that electrode. This can occur when water molecules are reduced at the electrode, producing hydroxide ions and hydrogen gas. Therefore, the salt solution that was electrolyzed must contain a cation that can be reduced to form hydroxide ions.

Options:
A) KCl
B) CuCl2
C) Cu(NO3)2
D) CuSO4

Explanation for each option:

A) KCl:
When KCl is electrolyzed, potassium ions (K+) and chloride ions (Cl-) are present in the solution. However, neither of these ions can be reduced to form hydroxide ions. The reduction of K+ ions would lead to the formation of potassium metal, not hydroxide ions. Therefore, KCl is unlikely to be the salt solution electrolyzed.

B) CuCl2:
When CuCl2 is electrolyzed, copper(II) ions (Cu2+) and chloride ions (Cl-) are present in the solution. Copper(II) ions can be reduced to form copper metal, but they cannot directly form hydroxide ions. Therefore, CuCl2 is unlikely to be the salt solution electrolyzed.

C) Cu(NO3)2:
When Cu(NO3)2 is electrolyzed, copper(II) ions (Cu2+) and nitrate ions (NO3-) are present in the solution. Similar to CuCl2, copper(II) ions can be reduced to form copper metal, but they cannot directly form hydroxide ions. Therefore, Cu(NO3)2 is unlikely to be the salt solution electrolyzed.

D) CuSO4:
When CuSO4 is electrolyzed, copper(II) ions (Cu2+) and sulfate ions (SO4^2-) are present in the solution. Copper(II) ions can be reduced to form copper metal, but sulfate ions cannot be directly reduced to form hydroxide ions. However, during the electrolysis of water, the sulfate ions can be oxidized at the anode to form oxygen gas and create an acidic environment. This acidic environment can lead to the migration of hydroxide ions towards the cathode, increasing the pH near the cathode. Therefore, CuSO4 is the most likely salt solution that was electrolyzed.