Question

Which is the most stable oxidation state of boron?

Answer 1

The inert s-pair effect is significant in the group-13 elements, especially the heavier ones like thallium. This results in a variety of oxidation states. In the lighter elements, the +3 state is the most stable, but the +1 state becomes more prevalent with increasing atomic number, and is the most stable for thallium. Boron is capable of forming compounds with lower oxidization states, of +1 or +2, and aluminium can do the same. Gallium can form compounds with the oxidation states +1, +2 and +3. Indium is like gallium, but its +1 compounds are more stable than those of the lighter elements. The strength of the inert-pair effect is maximal in thallium, which is generally only stable in the oxidation state of +1, although the +3 state is seen in some compounds. Stable and monomeric gallium, indium and thallium radicals with a formal oxidation state of +2 have since been reported.

Answer 2

the most stable oxidation state of Boron is +3 and this is because as mentioned in NCERT the group Oxidation State decides the most stable oxidation state of its lightest element... like for example, in group 13 since Boron is the lightest element as compared to all the other elements and the group Oxidation state number is + 3 so the most stable oxidation state of Boron is also + 3

Mark my answer as the brainiest.