What is the pH of buffer solution containing 10 times higher molar concentration of weak base than the molar concentration of salt of weak base with strong acid at 298 K? ( K_b of weak base = 10⁻⁵ )

Step-by-step solution

Using the Henderson-Hasselbalch equation for a basic buffer: pOH = pK_b + ( [Salt] [Base] ) Given K_b = 10⁻⁵ , we have pK_b = - (10⁻⁵) = 5 . It is given that the concentration of the weak base is 10 times the concentration of the salt, so [Base] = 10 [Salt] , which gives [Salt] [Base] = 1 10 . Substituting these values into the equation: pOH = 5 + ( 1 10 ) pOH = 5 - 1 = 4 At 298 K, the relationship between pH and pOH is: pH + pOH = 14 pH = 14 - 4 = 10 Answer: 10