A student tries to balance the equation by changing the subscript 2 on Cl to a 3. Explain why this is not correct. What is the correct balanced equation

The question is incomplete, the complete question is;

“Consider the unbalanced chemical equation. Al(s) + Cl2(g) > AlCl3(s) A student tries to balance the equation by changing the subscript 2 on Cl to a 3. Explain why this is not correct. What is the correct balanced equation?”

2Al(s) + 3Cl2(g) > 2AlCl3(s)

Explanation:

If the student changes the subscript of Cl from 2 to 3, he/she has written a symbol for a molecule that does not exist. Halogens exist as diatomic and not triatomic gases.

The balanced equation is; 2Al(s) + 3Cl2(g) > 2AlCl3(s).

Notice that the basic principles of valency are not violated in any of the species in the equation above. Cl3 violates the octet rule but Cl2 obeys the octet rule.

bcde is the incorrect answer it is a