To calculate the pH of the buffer solution, we can use the Henderson-Hasselbalch equation:pH = pKa + log [A-]/[HA] where pH is the pH of the solution, pKa is the negative logarithm of the dissociation constant Ka , [A-] is the concentration of the conjugate base sodium acetate , and [HA] is the concentration of the weak acid acetic acid .First, let's find the pKa value:pKa = -log Ka = -log 1.8x10^-5 4.74Now, we can plug the concentrations of acetic acid and sodium acetate into the equation:pH = 4.74 + log [0.1]/[0.1] Since the concentrations of the conjugate base and weak acid are equal, the log term becomes log 1 , which is 0. Therefore, the pH of the buffer solution is:pH = 4.74 + 0 = 4.74