General Chemistry

This is a summary practice problem set on buffer solutions aimed to help identify buffers, calculating the pH of a buffer solution prepared from a weak acid and its conjugate base or vice versa.

The links to the corresponding topics are given below:

Practice

1.

Which of the following solutions can be classified as buffer solutions?

(a) NaBr + HBr, (b) NaHSO4 + H2SO4, (c) HCl + HOCl (d) Na2HPO4 + NaH2PO4, (e) CH3CH2NH2 + CH3CH2NH3+ (f) NaNO2 + HNO2, (g) KCN + HCN, (h) Na2SO4 + NaHSO4, (i) NH3 + NH4ClO3, (j) CH3CO2H + NaOH.

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
2.

Addition of which salt will suppress the ionization of HOCl?

  1. Na2SO4
  2. KNO3
  3. NaOCl
  4. NaNO2
answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
3.

A solution of ammonia and ammonium chloride is a common buffer system. Write the corresponding reactions to show how it resists a pH change when an acid or a base is added to it.

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
4.

Calculate the pH of the buffer solution consisting of 0.75 M NH3 and 0.95 M NH4Cl. Kb (NH3) = 1.8 x 10-5.

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
5.

Calculate the pH of the buffer solution which is 1.4 M CH3COONa and 1.8 M CH3COOH. Ka (CH3CO2H) = 1.7 x 10-5

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
6.

Calculate the pH of the buffer solution that is 0.70 M NaCN and 0.55 M HCN. Ka (HCN) = 4.9 x 10-10

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
7.

Calculate the pH of the buffer solution that is 0.60 M propionic acid (CH3CH2CO2H) and 0.75 M sodium propionate. Ka (CH3CH2CO2H) = 1.32 x 10-5

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
8.

What is the pH of a buffer solution that is 0.85 M pyridine (C5H5N) and 1.3 M pyridinium chloride (C5H5NHCl)? Kb (C5H5N) = 1.7 x 10-9 16.82

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
9.

Calculate the pH of a solution that is 0.8 M HF and 2.0 M NaF. Ka (HF) = 6.6 x 10-4

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
10.

Calculate the ratio of NaNO2 to HNO2 required to create a buffer with pH = 4.00. Ka (HNO2 = 7.2 x 10-4)

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
11.

Assuming no volume change, how many grams of sodium benzoate (C7H5O2Na) needs to be added to 250.0 mL of a 0.25 M benzoic acid (C7H5O2H) solution to prepare a buffer with a pH of 4.60? Ka = 6.46 x 10-5

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
12.

How many mL of 0.60 M HF and 0.70 M NaF must be mixed to prepare 1.00 L of a buffer solution at pH of 4.2? pKa HF = 3.8

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
13.

What is the concentration of C6H5NH3Cl in the buffer solution with a pH of 4.3 containing 0.50 M C6H5NH2? Kb (C6H5NH2) 3.8 x 10-10

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
14.

Which of the following pairs is the best choice to prepare a buffer with pH = 3.2 ?

In what mass ratio would you add the components to prepare the buffer.

a) CH3COOH and CH3COONa b) HNO2 and KNO2 c) NH3 and NH4Cl d) C5H5N and C5H5NHCl.

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
15.

What would be the pH of a buffer solution composed of 0.60 M NH3/0.45 M NH4Cl after 0.010 mole of gaseous HCl is added to a 400.0 mL solution?

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
16.

Calculate the pH after 20.0 g NaOH(s) is added to 1.0 L of a buffer solution containing 1.80 M acetic acid and 1.50 M sodium acetate at pH 4.0.

 

answer
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
Solution
This content is available to registered users only. Click here to Register! By joining Chemistry Steps, you will gain instant access to the Answers and Solutions for all the Practice Problems, Quizzes, and the powerful set of General Chemistry 1 and 2 Summary Study Guides.  
17.

Check Also

Leave a Comment