What is the smallest amount of solid NaOH shown that will exceed the buffer capacity of 500 mL of a buffer that is 0.40 M in acetic acid and 0.15 M in sodium acetate. (K_a for acetic acid = 1.8 × 10^-5.) A) 8.00 g B) 5.16 g C) 4.74 g D) 4.31 g E) 3.00 g

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The buffer capacity is exceeded when the amount of strong base added is greater than the amount of weak acid present. The amount of acetic acid present is:$$0.40 	ext{ M} 	imes 0.500 	ext{ L} = 0.200 	ext{ mol}$$The amount of NaOH needed to exceed the buffer capacity is therefore:$$0.200 	ext{ mol} 	imes \frac{40.00 	ext{ g}}{1 	ext{ mol}} = 8.00 	ext{ g}$$

What Is the Smallest Amount of Solid NaOH Shown That