With all the coefficient set to 1, how can you tell that the equation is not balanced?

Well for any equation if all the coefficients are set to 1, this might result in unequal numbers of atoms of the same element on both sides

Explanation:

For example:

(for this equation all the coefficient (the number before element) are 1 but you can clearly see it is not balanced because one side has 1 A atom and other side has 2 B atoms....therefore we need to balance em.

Here both atoms are balanced.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.

catya your not at all which answer i've seen you do this on another question!