Explanation:

To determine which pair of electrolysis could be distinguished by the products of electrolysis using inert electrodes, we need to consider the reduction potentials of the ions present in each solution.

Reduction Potentials:
The reduction potential of an ion is a measure of its tendency to gain electrons and undergo reduction. It can be used to predict the product of electrolysis.

Using Inert Electrodes:
Inert electrodes, such as platinum or graphite, do not participate in the redox reactions during electrolysis. Therefore, the products of electrolysis are solely determined by the reduction potentials of the ions present in the solution.

Pair (a) - 1 M CuSO4 , 1 M CuCl2:
Both solutions contain copper ions (Cu2+) as the cation. Copper ions have a higher reduction potential than hydrogen ions (H+), so they will be reduced at the cathode instead of hydrogen ions. The anions (SO42- and Cl-) will not be reduced at the cathode. Therefore, the products of electrolysis will be the same for both solutions.

Pair (b) - 1 M KCl , 1 M KI:
The reduction potentials of the cations (K+) are the same for both solutions. However, the reduction potentials of the anions (Cl- and I-) are different. Chloride ions (Cl-) have a higher reduction potential than iodide ions (I-). Therefore, when using inert electrodes, chloride ions will be preferentially reduced at the cathode in the KCl solution, while iodide ions will be preferentially reduced at the cathode in the KI solution. This difference in reduction products allows us to distinguish between the two solutions.

Pair (c) - 1 M AgNO3, 1 M CuSO4:
Both solutions contain different cations (Ag+ and Cu2+). The reduction potentials of these cations are different. Therefore, the products of electrolysis will be different for each solution, allowing us to distinguish between them.

Pair (d) - 1 M CuBr2 , 1 M NiBr2:
Both solutions contain different cations (Cu2+ and Ni2+). The reduction potentials of these cations are different. Therefore, the products of electrolysis will be different for each solution, allowing us to distinguish between them.

Conclusion:
From the above analysis, we can conclude that pair (b) - 1 M KCl , 1 M KI and pair (c) - 1 M AgNO3, 1 M CuSO4 can be distinguished by the products of electrolysis using inert electrodes.