This formula equation is unbalanced. P4(s) + Cl2(g) Right arrow. PCl3(l) Which coefficient should be placed in front of PCl3 to balance this equation?

The balance equation is:

P₄(s) + 6Cl₂(g) → 4PCl₃(l)

Therefore the coefficient that should be placed in front of PCl₃ is 4

Explanation:

The unbalanced reaction is:

P₄(s) + Cl₂(g) → PCl₃(l)

As we have 4 atoms of P, we need to add 4 in front of the PCl₃ but now we unbalance the chlorine.

In 4 moles of PCl₃ we have 12 Cl, so we must add 6 in the Cl₂ on the reactant side.

The balance equation will be:

P₄(s) + 6Cl₂(g) → 4PCl₃(l)

it's all four options.