How does the way a buffer stabilizes ph during addition of acid differ from the way the same buffer stabilizes ph during addition of base?

Buffer solution is made up of weak acid or base with its conjugate salt. It resists the change in pH of the solution. When acid or base is added to the buffer solution, the pH gets stabilized but the direction of reaction is opposite. Thus, the reaction is same but the one moves backward and other moves in forward direction.

A buffer solution can be defined as:

HA +NaA

Here, NaA is in dissociated form as follows:

NaA\rightarrow Na^{+}+A^{-}

when acid is added it reacts with A^{-} to form HA and reaction moves in backward direction. When base is added it reacts with HA to form more A^{-}  and reaction moves in forward direction.

If acid is added

indium, and thallium have three electrons i think