Question

Phosphorus pentachloride is formed when 17.2 g of chlorine gas react with 23.2 g of solid phosphorus (P2). Determined the reactant that is in excess

Answer 1

Here is the equation:

P₂ + 5Cl₂ --> 2PCl₅

$n(P_2)=23.2\ g\times\frac{1\ mol}{61.95\ g}=0.374\ mol$

$n(Cl_2)=17.2\ g\times\frac{1\ mol}{70.91\ g}=0.243\ mol$

According to the equation, P₂ and Cl₂ react in 1 : 5 molar ratio. The actual ratio is 0.374 : 0.243, which indicates the significant excess of P₂.

Answer: P₂