Answer:
a. chromium (III) chloride
Step-by-step explanation:
Chromium chloride is also binary ionic compound composed of only two element chromium and chlorine.
When naming these compounds the name of metal or cation is written first and anion is written after the cation. The anions are non meals.
The anion name is end with suffix " ide".
such as chromium chloride.
The (III) shows the oxidation number of metal. In given compound the oxidation state of chromium is +3 while chlorine chow the oxidation state of -1 that's why three chlorine atoms are attached with one chromium atom.