Question

QUESTION 1

If you have a solution with 1 mole of the base (CH₃)₃N, which of the following can be added to make a buffer? Choose all correct answers.

		(CH
		0.6 mol HCl
		0.4 mol NaOH
		(CH
		1 mol NaOH
		1 mol HCl

1 points   

QUESTION 2

Which of the following occurs when NaOH is added to a buffer containing (CH₃)₃N and (CH₃)₃NH⁺?  

Select all that apply.

		The concentraion of
		The pH will decrease.
		The concentraion of
		(CH
		The pH will increase.
		The concentraion of

1 points   

QUESTION 3

When NaOH is added to a HF / NaF buffer, what happens to the following values?

-       A.       B.	Concentration of HF
-       A.       B.	Concentration of F-?
-       A.       B.	pH

A.	Decreases
B.	Increases

1 points   

QUESTION 4

Of the following, which is the best base to create a buffer with a pH = 8.0?

		Aniline, Kb = 4.3 x 10-10
		Pyridine, Kb = 1.7 x 10-9
		Ethylamine, K
		Hydrazine, K

Answer 1

Question 1

Buffer solution can be prepared by mixing an aqeous solution of weak base and its conjugate acid or vice-e-versa

Here base is (CH₃)₃N which is a weak base

Its conjugate acid (CH₃)₃NHCl or (CH₃₎₃NHNO₃

So both (CH₃)₃NHCl and (CH₃)₃NHNO₃ can be used to make the buffer solution

Question 2

The concentraion of (CH₃)₃NH⁺ will decrease.

The concentraion of (CH₃)₃N will increase

Question 3

When NaOH is added to a HF / NaF buffer, what happens to the following values:

The Concentration of F- will increase

The concentration of HF will decrease

pH of the solution remain constant

Question 4

The best base to make the buffer is hydrazine

K_b of hydrzine is 1.3*10^-6 (so ka = 7.69 X 10-9) pKa = 8.11