Arrange the following compounds as asked : (a) in decreasing order of $\text{pK}_\text{b}$ values $\text{C}_2\text{H}_5\text{NH}_2, (\text{C}_2\text{H}_5)_2\text{NH}, \text{C}_6\text{H}_5\text{NHCH}_3, \text{C}_6\text{H}_5\text{NH}_2$ (b) increasing order of boiling point $\text{C}_2\text{H}_5\text{OH}, \text{C}_2\text{H}_5\text{NH}_2, (\text{CH}_3)_2\text{NH}$ (c) increasing order of solubility in water $\text{C}_6\text{H}_5\text{NH}_2, (\text{C}_2\text{H}_5)_2\text{NH}, \text{C}_2\text{H}_5\text{NH}_2$