Please use correct units and show sig digs. Practice: You need to prepare 3.00 L
ID: 573311 • Letter: P
Question
Please use correct units and show sig digs.
Practice: You need to prepare 3.00 L of a 0.500 M buffer of pH 5.80. The reagents available to you are listed in Table 1. Table 2 shows the pK s for the acids in Table 1 Table 1: Potassium dihydrogencitrate Malonic acid Sodium hydrogen succinate Disodium maleate HCL NaQH (230.2 g/mol) (104.1 g/mol) (140.1 g/mol) (160.0 g/mol) (12.0 M) (10.0 M) Table 2: Acid citric malonic ucciniC maleic pKa 3.14 2.83 4.21 1.83 pKaz 4.77 5.69 5.63 6.07 pKa, 6.39 a. Which of the reagents from Table 1 would you use for making the buffer? b. Calculate how much of each reagent (and water) you would use to make this buffer. From Table 1, select a second set of reagents that you could use to make a buffer of the same pH and concentration c. d. How much of each reagent and water would you use to make this buffer?Explanation / Answer
a) Malonic acid and disodium maleate
b)according to the following equation we can find the ratio between the weak acid and its salt
Pka= pH + log(acid/base)
For pka we should select the pka of melodic acid as it is the weak acid we use and 5.69 as the pka as it is close to pH 5.8.
d) potassium dihydrogencitrate as the concentration of it is closer to the sum of concentration of melodic acid and disodium maleate
d) by finding the moles of the buffer and using c=n/v we can find the amount of the reagent needed