Primary valency of binary compound ${\mathrm{CrCl}}_3, {\mathrm{CoCl}}_2 \mathrm{and} {\mathrm{PdCl}}_2$ are

Primary valency corresponds to the oxidation state of metal. Thus, in the given binary compounds ${\mathrm{CrCl}}_3, {\mathrm{CoCl}}_2 \mathrm{and} {\mathrm{PdCl}}_2$, the primary valencies are 3, 2 and 2 respectively.