Question

a. Describe the preparation of 2 liters of 0.1 M Glutamate buffer, pH 10.0. You have available monosodium glutamate (MW=169), 0.5M NaOH and distilled water.

b. Momentarily distracted by having a piece of old light fixture fall on your head, you add 10ml of the 0.5 HCL to the 2L of buffer. What would be the pH now?

Answer 1

Solution:

Part (a)

for 0.1 M buffer in 2 litres the preparation is as,

As first step add 4 gm of NaOH to 1 lt distilled water and shake till it dissolves completely, then next to it add 33.8 gm of monosodium glutamate to another 1 lt and dissolve, finally mix both the solution for achieving 0.1 M glutamate buffer.

Part (b)

by using hendersen-hasselbalch equation,

pK = pH + log {[Conjucate acid] / [Conjugate base]}

14 = pH + log { [0.5] / [0.1]}

14 = pH + 0.4771

pH = 14 - 0.4771

pH = 13.5228