Final answer:
In the balanced equation for the reaction of indium with chlorine to form indium trichloride (InCl3), the coefficient of InCl3 is 1, as indium forms a +3 ion and chlorine forms a -1 ion.
Step-by-step explanation:
When indium reacts with chlorine to form InCl3, we follow similar logic to other synthesis reactions, where we consider the charges of the ions forming the compound. Indium will typically form a +3 ion, and chlorine, being a Group VII element, will form a -1 ion. The balanced equation for the reaction between indium and chlorine to form indium trichloride (InCl3) would require one indium atom to react with three chlorine atoms, resulting in one formula unit of indium trichloride. Therefore, the coefficient of indium trichloride in the balanced equation is 1.
The balanced equation will look like this:
2 In (s) + 3 Cl2 (g) → 2 InCl3 (s)
As per the balanced equation, two atoms of indium react with three molecules of chlorine gas to produce two formula units of indium trichloride. Hence, the coefficient in front of InCl3 is indeed A) 1.