For one a homogenous mixture cannot be separated using filtration. Hope this helps:)
The first option is the correct.
Since we know the mass of one atom of Fe is 56 and that of Cl2 atoms is 71 (one atom has 35.5 mass) hence both of them will be consumed
It states the fact, which we now know, that electrons are responsible for the chemical bonding. According to this theory, valency is the number of electrons present in the outermost energy shell of the atom. This energy shell is called valency shell.