Solution Found!
Given that C6H11COOH has a pKa = 4.8 and has a pKa = 10.7,
Chapter 2, Problem 42P(choose chapter or problem)
Given that \(\mathrm{C}_{6} \mathrm{H}_{11} \mathrm{COOH}\) has a \(p K_{a}=4.8\) and \(C_{6} H_{11} N^{+} H_{3}\) has a \(p K_{a}=10.7\), answer the following:
a. What pH would you make the water layer in order to cause both compounds to dissolve in it?
b. What pH would you make the water layer in order to cause the acid to dissolve in the water layer and the amine to dissolve in the ether layer?
c. What pH would you make the water layer in order to cause the acid to dissolve in the ether layer and the amine to dissolve in the water layer?
Equation Transcription:
Text Transcription:
C_6 H_11 COOH
pK_a =4.8
C_6 H_11 N^+ H_3
pK_a =10.7
Questions & Answers
QUESTION:
Given that \(\mathrm{C}_{6} \mathrm{H}_{11} \mathrm{COOH}\) has a \(p K_{a}=4.8\) and \(C_{6} H_{11} N^{+} H_{3}\) has a \(p K_{a}=10.7\), answer the following:
a. What pH would you make the water layer in order to cause both compounds to dissolve in it?
b. What pH would you make the water layer in order to cause the acid to dissolve in the water layer and the amine to dissolve in the ether layer?
c. What pH would you make the water layer in order to cause the acid to dissolve in the ether layer and the amine to dissolve in the water layer?
Equation Transcription:
Text Transcription:
C_6 H_11 COOH
pK_a =4.8
C_6 H_11 N^+ H_3
pK_a =10.7
ANSWER:Solution:
Here it has been given that the pKa of C6H11COOH is equal to 4.8 and pKa of C6H11NH+3 = 10.7.
Step 1
a. Here we have to find out that at what pH of the water layer both the compounds will dissolve in it.
It is known that the ionized compounds are soluble in water i.e the compounds that have charge are soluble in water and the pH of the water layer in which compounds dissolve, must have two units less than pKa of the compounds.
Here carboxylic acid is not charged having pKa = 4.8, it can form a carboxylate ion. So pH will be increase b y two units i.e 6.8.
Similarly the ammonium ion (C6H11NH+3) has pKa = 10.7 and it is a charged compound. Thus its pH should be less than two units i.e 8.7.
Hence to dissolve both the compounds water layer must have pH in the range 6.8-8.7.