Concept explainers
(a)
Interpretation:
The pH of the given buffer is to be calculated.
Concept Introduction:
The buffer is a solution that resists any change in pH on addition of
(b)
Interpretation:
The pH of the given buffer is to be calculated.
Concept Introduction:
The buffer is a solution that resists any change in pH on addition of
(c)
Interpretation:
The pH of the given buffer is to be calculated.
Concept Introduction:
The buffer is a solution that resists any change in pH on addition of
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Chemistry for Today: General, Organic, and Biochemistry
- An aqueous solution contains dissolved C6H5NH3Cl and C6H5NH2. The concentration of C6H5NH2 is 0.50 M and pH is 4.20. a. Calculate the concentration of C6H5NH3+ in this buffer solution. b. Calculate the pH after 4.0 g NaOH(s) is added to 1.0 L of this solution. (Neglect any volume change.)arrow_forwardChloropropionic acid, ClCH2CH2COOH, is a weak monoprotic acid with Ka = 7.94 105. Calculate the pH at the equivalence point in a titration of 10.00 mL of 0.100 M chloropropionic acid with 0.100 M KOH. Choose an indicator from Table 16.4 for the titration. Explain your choice. TABLE 16.5 Properties of Several Indicatorsarrow_forwarda Draw a pH titration curve that represents the titration of 50.0 mL of 0.10 M NH3 by the addition of 0.10 M HCl from a buret. Label the axes and put a scale on each axis. Show where the equivalence point and the buffer region are on the titration curve. You should do calculations for the 0%, 30%, 50%, and 100% titration points. b Is the solution neutral, acidic, or basic at the equivalence point? Why?arrow_forward
- Ka for formic acid is 1.7 104 at 25C. A buffer is made by mixing 529 mL of 0.465 M formic acid, HCHO2, and 494 mL of 0.524 M sodium formate, NaCHO2. Calculate the pH of this solution at 25C after 110 mL of 0.152 M HCl has been added to this buffer.arrow_forwardIf added to 1 L of 0.20-M acetic acid, CH3COOH, which of these would form a buffer? 0.10 mol NaCH3COO 0.10 mol NaOH 0.10 mol HCl 0.30 mol NaOH Explain your answers.arrow_forwardA student dissolves 0.0100 mole of an unknown weak base in 100.0 mL water and titrates the solution with 0.100 M HNO3. After 40.0 mL of 0.100 M HNO3 was added, the pH of the resulting solution was 8.00. Calculate the Kb value for the weak base.arrow_forward
- Briefly describe how a buffer solution can control the pH of a solution when strong acid is added and when strong base is added. Use NH3/NH4Cl as an example of a buffer and HCl and NaOH as the strong acid and strong base.arrow_forwardA 0.239-g sample of unknown organic base is dissolved in water and titrated with a 0.135 M hydrochloric acid solution. After the addition of 18.35 mL of acid, a pH of 10.73 is recorded. The equivalence point is reached when a total of 39.24 mL of HCl is added. The base and acid combine in a 1:1 ratio. a What is the molar mass of the organic base? b What is the Kb value for the base? The Kb value could have been determined very easily if a pH measurement had been made after the addition of 19.62 mL of HCl. Why?arrow_forwardA buffer is composed of formic acid and its conjugate base, the formate ion. (a) What is the pH of a solution that has a formic acid concentration of 0.050 M and a sodium formate concentration of 0.035 M? (b) What must the ratio of acid to conjugate base be to have a pH value 0.50 units higher than the value calculated in part (a)?arrow_forward
- A buffer solution was prepared by adding 4.95 g sodium acetate to 250. mL of 0.150-M acetic acid. What ions and molecules are present in the solution? List them in order of decreasing concentration. Calculate the pH of the buffer solution. Calculate the pH of 100. mL of the buffer solution if you add 80. mg NaOH. (Assume negligible change in volume.) Write a net ionic equation for the reaction that occurs to change the pH.arrow_forwardConsider 1.0 L of a solution that is 0.85 M HOC6H5 and 0.80 M NaOC6H5. (Ka for HOC6H5 = 1.6 1010.) a. Calculate the pH of this solution. b. Calculate the pH after 0.10 mole of HCl has been added to the original solution. Assume no volume change on addition of HCl. c. Calculate the pH after 0.20 mole of NaOH has been added to the original buffer solution. Assume no volume change on addition of NaOH.arrow_forwardEnough water is added to the buffer in Question 29 to make the total volume 10.0 L. Calculate (a) the pH of the buffer. (b) the pH of the buffer after the addition of 0.0500 mol of HCl to 0.600 L of diluted buffer. (c) the pH of the buffer after the addition of 0.0500 mol of NaOH to 0.600 L of diluted buffer. (d) Compare your answers to Question 29(a)-(c) with your answers to (a)-(c) in this problem. (e) Comment on the effect of dilution on the pH of a buffer and on its buffer capacity.arrow_forward
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