Introduction:
When an aqueous copper sulphate solution and an aqueous silver nitrate solution are electrolysed, the copper and silver ions present in the solutions are reduced at the cathode, resulting in the deposition of copper and silver metal.

Explanation:
The mass of copper and silver deposited on the cathode will be different due to the difference in the amount of charge required to reduce each metal ion. This can be explained by Faraday's laws of electrolysis.

Faraday's First Law:
According to Faraday's first law, the mass of a substance deposited at an electrode during electrolysis is directly proportional to the amount of charge passed through the electrolyte.

Faraday's Second Law:
Faraday's second law states that the mass of different substances deposited by the same amount of charge is directly proportional to their respective chemical equivalent masses.

Determination of Mass Deposited:
To determine the mass of copper and silver deposited, we need to calculate the amount of charge passed through the electrolyte and use the chemical equivalent masses of copper and silver.

Calculation:
1. The amount of charge passed can be calculated using the formula:
Charge (Coulombs) = Current (Amperes) × Time (seconds)

2. The chemical equivalent mass of a substance is the mass of the substance deposited by one Faraday of charge.
For copper, the chemical equivalent mass is the molar mass of copper, divided by the valency of copper (2+).
For silver, the chemical equivalent mass is the molar mass of silver, divided by the valency of silver (1+).

3. The mass of copper deposited can be calculated by multiplying the amount of charge passed with the chemical equivalent mass of copper.
Mass of Copper (grams) = Charge (Coulombs) × Chemical Equivalent Mass of Copper (grams)

4. Similarly, the mass of silver deposited can be calculated using the amount of charge passed and the chemical equivalent mass of silver.
Mass of Silver (grams) = Charge (Coulombs) × Chemical Equivalent Mass of Silver (grams)

Conclusion:
The mass of copper and silver deposited on the cathode will be different due to the difference in their chemical equivalent masses. Copper has a higher chemical equivalent mass than silver, so for the same amount of charge passed, a greater mass of copper will be deposited compared to silver.