Concept explainers
A buffer contains
a.
b. Both
c. Both
d.
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Introducing Chemistry
- 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_forwardIndicate whether each of the following statements is true or false. If the statement is false, restate it to make it true. (a) The formate ion (CHO2-) concentration in 0.10 M HCHO2 is the same as in 0.10 M NaCHO2. (b) A buffer can be destroyed by adding too much strong acid. (c) A buffer can be made up by any combination of weak acid and weak base. (d) Because Ka for HCO3- is4.71011, Kb for HCO3- is2.1104.arrow_forwardConsider the titration of 100.0 mL of 0.100 M HCN by 0.100 M KOH at 25C. (Ka for HCN = 6.2 1010.) a. Calculate the pH after 0.0 mL of KOH has been added. b. Calculate the pH after 50.0 mL of KOH has been added. c. Calculate the pH after 75.0 mL of KOH has been added. d. Calculate the pH at the equivalence point. e. Calculate the pH after 125 mL of KOH has been added.arrow_forward
- Consider 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_forwardA 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_forwardA buffer solution that is 0.100 M acetate ion and 0.100 M acetic acid is prepared. (a) Calculate the initial pH, final pH, and change in pH when 1.00 mL of 1.00 M NaOH is added to 100.0 mL of the buffer. (b) Calculate the initial pH, final pH, and change in pH when 1.00 mL of 1.00 M NaOH is added to 100.0 mL pure (pH 7.00) water.arrow_forward
- Enough 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_forwardYou titrate 25.0 mL of 0.10 M NH3 with 0.10 M HCl. (a) What is the pH of the NH3 solution before the titration begins? (b) What is the pH at the equivalence point? (c) What is the pH at the halfway point of the titration? (d) What indicator in Figure 17.11 could be used to detect the equivalence point? (e) Calculate the pH of the solution after adding 5.00, 15.0, 20.0, 22.0, and 30.0 mL of the acid. Combine this information with that in parts (a)(c) and plot the titration curve.arrow_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
- Calculate the pH after 0.15 mole of solid NaOH is added to 1.00 L of each of the following solutions: a. 0.050 M propanoic acid (HC3H5O2, Ka = 1.3 105) and 0.080 M sodium propanoate b. 0.50 M propanoic acid and 0.80 M sodium propanoate c. Is the solution in part a still a buffer solution after the NaOH has been added? Explain.arrow_forwardLactic acid (CH3CHOHCO2H) is found in sour milk, in sauerkraut, and in muscles after activity. (Ka for lactic acid = 1.4 104.) (a) If 2.75 g of NaCH3CHOHCO2, sodium lactate, is added to 5.00 102 mL of 0.100 M lactic acid, what is the pH of the resulting buffer solution? (b) Is the pH of the buffered solution lower or higher than the pH of the lactic acid solution?arrow_forwardWhich compound in each pair is more soluble in water than is predicted by a calculation from Ksp? (a) AgI or Ag2CO3 (b) PbCO3 or PbCl2 (c) AgCl or AgCNarrow_forward
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