Question

If equal volumes of 0.1 M HCl and 0.2 M TRIS (base form) are mixed together. The pKa of TRIS is 8.30. Which of the following statements about the resulting solution are correct?
(Select all that apply.)

A. The ratio of [conjugate base]/[conjugate acid] is [0.1 M]/[0.05 M].
B. This solution is too basic to be a buffer.
C. The ratio of [conjugate base]/[conjugate acid] is [0.05 M]/[0.05 M].
D. This solution is a good buffer.
E. The majority of TRIS will be in the acid form in the solution.

Answer 1

Answer:

option D is correct

D. This solution is a good buffer.

Explanation:

TRIS (HOCH$_{2}$)$_{3}$CNH$_{2}$

if TRIS is react with HCL it will form salt

(HOCH$_{2}$)$_{3}$CNH$_{2}$ + HCL ⇆   (HOCH$_{2}$)$_{3}$NH$_{3}$CL

Let the reference volume is 100

Mole of TRIS is =  100 × 0.2 = 20

Mole of HCL is =  100 × 0.1 = 10

In the reaction all of the HCL will Consumed,10 moles of the salt will form

and 10 mole of TRIS will left

hence , Final product will be salt +TRIS(9 base)

H = Pk$_{a}$ + log (base/ acid)

8.3 + log(10/10)

8.3