IUPAC name of the complex, $\left[\mathrm{Cr}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5{\mathrm{Cl}}_{ }\right]{\mathrm{Cl}}_2$ is

${\mathrm{H}}_2\mathrm{O}...$aqua…neutral ligand ;

${\mathrm{Cl}}^{-}$….chlorido or chloro(preferably chlorido)….uninegative ligand ;

Oxidation state of chromium is “+3” ;

Counter ion is chloride ion and while naming the counter ion  prefixes like di, `tri…should not be used;

Complex ion is a cation, it is named first followed by anion or anions;

For cationic or neutral complex, name of metal remains same (no need to add “ate” at end of name of metal).

While naming the complex, ligands are named first (in alphabetical order with proper prefixes) followed by metal ion with its oxidation state as roman number in parenthesis;

The name of the complex is pentaaqua chlorido chromium(III) chloride;