Question

12. Phosphorus (P) reacts with chlorine to form phosphorus trichloride. If we have 1.45g of produced? phosphorus , what mass of chlorine is required to react completely? How much product can be

Answer 1

The reaction between phosphorous and chlorine is given by
P4(s) + 6 Cl2(g) -----------> 4PCl3(g)
1mole P4 + 6 moles Cl2 -----> 4moles PCl3
Molar mass of P4 = 124 g/mol
Molar mass of Cl2 = 71 g/mol

From stoichiometry of reaction,
1mole of P4 reacts with 6 moles of Cl2

Moles of P4 given = 1.45 g/124 g/mol = 0.017 moles
Moles of Cl2 required = 0.0117 x 6 = 0.0702 moles

AMount of Cl2 = moles x mol.wt
= 0.0702 x 71 = 4.98 gms

1mole of P4 gives 4 moles product

0.0117 moles of P4 on complete reaction with Cl2 produces

0.0117 x 4 = 0.0468 moles

Amount of PCl3 that can be formed = moles x molar mass

= 0.0468 x 137 g/mol = 6.41 gms