Question

The reducing character of Al, Ga, In, Tl increases in which of the following order?
A. Tl < Al < Ga < In
B. Ga < Al < Tl < In
C. Tl < In < Ga < Al
D. Al < Ga < In < Tl

Answer 1

The reducing character of the element decreases as the electrode potential increases, on going down in the respective group. Rather, the reducing character is inversely proportional to the electrode potential, for the elements of group 13.

Complete answer:
In electrochemistry, electrode potential is that the emf generated from a voltaic cell built from a regular reference electrode and another electrode to be characterized. By convention, the reference electrode is that the standard hydrogen electrode (SHE). it's defined to own a possible of zero volts.
The electrode potential has its origin within the potential developed at the interface between the electrode and also the electrolyte. it's common, for example, to talk of the electrode potential of the ${{M}^{+}}/M$ redox couple
Electrode potential appears at the interface between an electrode and electrolyte, the reason being the transfer of charged species across the interface, specific adsorption of ions at the interface, and specific adsorption/orientation of polar molecules, including those of the solvent.
The tendency of any substance to scale back other substances is called its reducing character similarly the tendency of any substance to oxidize other substances is called its oxidizing character . When a substance loses oxygen or gains hydrogen during a reaction, it's reduced. In the group 13 elements, the electrode potential increases on going down the group. So, Aluminium, being at the lowest, has the maximum reducing character, and Tl the least.

So, we obtain the order of decreasing character as Tl < In < Ga < Al, which gives us option C as the answer.

Note:
There is also a term called reduction potential, which is a measure of the tendency of a chemical species to gain or lose electrons to an electrode and hence, be reduced or oxidised respectively.