°ΔG rxn = -1108.7
Further explanation
Maybe the question is like this
the value of ΔG° at 25 °C for the formation of POCl₃
Reaction
P₂(g)+O₂(g)+3Cl₂(g)⇒2POCl₃(g)
Formula
![\tt ^o\Delta G_(rxn)=^o\Delta G_f~product-^o\Delta G_f~reactants](https://img.qammunity.org/2021/formulas/chemistry/high-school/hb8wrpjy7zklq4a3alo27q6hpsvul0nrjj.png)
You can find table to find ΔG° at 25 °C(298 K)
°ΔG POCl₃ = -502.5 kJ/mol
°ΔG O₂ and °ΔG Cl₂ = 0
°ΔG P₂ = 103.7 kJ/mol
![\tt ^o\Delta G_(rxn)=2.^o\Delta G~POCl_3-^o\Delta GP_2\\\\^\Delta G_(rxn)=2.(-502.5)-103.7=-1108.7~kJ/mol](https://img.qammunity.org/2021/formulas/chemistry/high-school/5falidapr2jkrqvcftma41uq1b0jxrj0yb.png)