$\left(\mathrm{A}\right)=\mathrm{C}\mathrm{r}{\mathrm{O}}_2\mathrm{C}{\mathrm{l}}_2$
$\left(\mathrm{B}\right)=\mathrm{N}{\mathrm{a}}_2\mathrm{C}\mathrm{r}{\mathrm{O}}_4$
$\left(\mathrm{C}\right)=\mathrm{C}\mathrm{r}{\mathrm{O}}_5$

Chromyl chloride $\left({\mathrm{CrO}}_2{\mathrm{Cl}}_2\right)$ can be prepared by the reaction of potassium chromate or potassium dichromate with hydrogen chloride in the presence of sulfuric acid, followed by distillation. The sulfuric acid serves as the dehydration agent.