Can someone explain the Henderson-Hasselbalch equation?

Question

I don't get how it's formed....what the premise is ...(why and how are we finding pH from pKa, etc...)

I just don't understand it....can someone clear it up?

Answer 1

The "H-H" equation deals with the dissociation of weak acids or bases in water. Whereas strong acids and bases become totally ionized in water, the weak acids and bases are just slightly ionized in water. The measure of the extent of ionization is Ka (for acids) or Kb(for bases). If the initial amount of the weak acid HA added is A moles/liter, the equilibrium situation is given by:
HA = H+ + A-
If x moles/liter dissociate, then
[H+][A-]/[HA] = Ka = (x * x)/(A-x)
Usually, x<

Answer 2

x=5t-2r+QW