A buffer solution was prepared by mixing 5 g of acetic acid with 7.5 g of sodium acetate. The solution was made upto 500 mL . The pH of the resulting solution is: [p K_a=4.76 ]

Step-by-step solution

The molar mass of acetic acid ( CH₃COOH ) is 60 g/mol . The number of moles of acetic acid is n_ acid = 5 60 = 1 12 mol . The molar mass of sodium acetate ( CH₃COONa ) is 82 g/mol . The number of moles of sodium acetate is n_ salt = 7.5 82 0.09146 mol . Using the Henderson-Hasselbalch equation for an acidic buffer: pH = pK_ a + ( [salt] [acid] ) . Since the volume is the same for both components in the 500 mL solution, the ratio of concentrations is equal to the ratio of moles: pH = pK_ a + ( n_ salt n_ acid ) . pH