A: $\frac{\left(\mathrm{CH}_3 \mathrm{CO}\right)_2 \mathrm{O}}{\mathrm{H}^{+}}$      $\mathrm{B}: \frac{\mathrm{CH}_3 \mathrm{CHO}}{\mathrm{H}^{+}}$

A: $\frac{\mathrm{CH}_3 \mathrm{COO}^{-}}{\mathrm{OH}^{-}}$    B: $\frac{\mathrm{CH}_3 \mathrm{Cl}}{\text { (warm) }}$

$\mathrm{A}: \frac{\mathrm{CH}_3 \mathrm{OH}}{\mathrm{H}^{+}}$    B: $\frac{\left(\mathrm{CH}_3 \mathrm{CO}\right)_2 \mathrm{O}}{\mathrm{H}^{+}(\text {warm })}$

$$ \mathrm{A}=\frac{\mathrm{CH}_3 \mathrm{COCl}}{(\text { warm })} \quad \mathrm{B}=\frac{\mathrm{CH}_3 \mathrm{Br}}{(\text { warm })} $$

Kolbe's reaction, Ethanoic acid

Esterification, methyl ethanoate

Hell-Volhard-Zelinsky reaction, 2-chloro-ethanoic acid

Riemer-Tiemann reaction, 1-chloro-ethanoic acid