Arrange the following compounds as asked:
(a) In decreasing order of pKb values
C2H5NH2, (C2H5)2NH, C6H5NHCH3, C6H5NH2
(b) In increasing order of boiling point
C2H5OH, C2H5NH2, (CH3)2NH
(c) In increasing order of solubility in water
C6H5NH2, (C2H5)2NH, C2H5NH2
(a) In decreasing order of pKb values
C2H5NH2, (C2H5)2NH, C6H5NHCH3, C6H5NH2
(b) In increasing order of boiling point
C2H5OH, C2H5NH2, (CH3)2NH
(c) In increasing order of solubility in water
C6H5NH2, (C2H5)2NH, C2H5NH2
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Solution and Explanation
(a) Decreasing order of pKb values (i.e., increasing basicity):
\( (\text{C}_2\text{H}_5)_2\text{NH}>\text{C}_2\text{H}_5\text{NH}_2>\text{C}_6\text{H}_5\text{NHCH}_3>\text{C}_6\text{H}_5\text{NH}_2 \)
(b) Increasing order of boiling point:
\( (\text{CH}_3)_2\text{NH}<\text{C}_2\text{H}_5\text{NH}_2<\text{C}_2\text{H}_5\text{OH} \)
(c) Increasing order of solubility in water:
\( \text{C}_6\text{H}_5\text{NH}_2<(\text{C}_2\text{H}_5)_2\text{NH}<\text{C}_2\text{H}_5\text{NH}_2 \)
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