Question

chlorine gas reacts with solid phosphorus to form phosphorus trichloride gas. write a balanced chemical equation for this reaction.

Explanation:

Step1: Write the reactants and products

The reactants are chlorine gas ($Cl_2$) and solid phosphorus ($P$), and the product is phosphorus trichloride gas ($PCl_3$). So the un - balanced equation is $P + Cl_2
ightarrow PCl_3$.

Step2: Balance the chlorine atoms

There are 2 chlorine atoms in $Cl_2$ and 3 chlorine atoms in $PCl_3$. The least - common multiple of 2 and 3 is 6. So we need 3 moles of $Cl_2$ and 2 moles of $PCl_3$ to balance the chlorine atoms: $P+3Cl_2
ightarrow 2PCl_3$.

Step3: Balance the phosphorus atoms

Now, to balance the phosphorus atoms, we need 2 moles of $P$ on the left - hand side. The balanced chemical equation is $2P + 3Cl_2
ightarrow 2PCl_3$.

Answer:

$2P(s)+3Cl_2(g)
ightarrow 2PCl_3(g)$