Arrange the following in the increasing order of the property mentioned :
$$\begin{gathered} \text{ (a) }{\mathrm{CH}}_3\mathrm{COOH},{\mathrm{ClCH}}_2\mathrm{COOH},{\mathrm{FCH}}_2\mathrm{COOH}\text{ ( Acidic Strength) } \\ \text{ (b) }{\mathrm{CH}}_3\mathrm{CHO},{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH},{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_3 (\mathrm{Boiling} \mathrm{points}) \end{gathered}$$

a. Electron withdrawing groups increase the acidity of carboxylic acids by stabilizing the conjugate base through delocalization of the negative charge by inductive and/or resonance effects. Conversely, electron donating groups decrease the acidity by destabilizing the conjugate base.

The effect of the following groups in increasing acidity order is
Ph < I < Br < Cl < F < CN < NO₂ < CF₃
Hence, ${\mathrm{CH}}_3\mathrm{COOH}<{\mathrm{ClCH}}_2\mathrm{COOH}<{\mathrm{FCH}}_2\mathrm{COOH}$
b. The boiling points of aldehydes and ketones are higher than hydrocarbons and ethers of comparable molecular masses. It is due to weak molecular association in aldehydes and ketones arising out of the dipole-dipole interactions. Also, their boiling points are lower than those of alcohols of similar molecular masses due to absence of intermolecular hydrogen bonding.
Thus, the order is ${\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{CH}}_3<{\mathrm{CH}}_3\mathrm{CHO}<{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}$