How an acidic buffer solution works. Buffer solutions resist a change in pH when small amounts of acid or alkali are added.

Composition of a buffer solution.  Consist of a weak acid mixed with its salt in equal amounts - such that [HA] = [A-]  Example ethanoic acid/ethanoate. Lots of HA and A- Show equilibria. Show equation HA to H+ + A-.

Perhaps animation (if budget/numbers left) for this part: Show equilibrium. If small amount H+ added, equilibrium shifts to remove it, ie left. As extra H+ removed, pH fairly constant. Similarly if OH- added...

Explaining what is happening in terms of equilibrium shift.  The salt of the weak acid provides the conjugate base in the solution. Absorbs the H+ ions coming from the addition of the small amount of HCl.

Similar for alkaline buffer. Go though example - as part of the animation? Or get people thinking it though by click and reveal. (which way will equilibrium shift? etc)