Answer:
[tex]\boxed {\boxed {\sf 1 \ mole \ P_4 consumed \ to \ 4 \ moles \ PBr_3 \ produced}}[/tex]
Explanation:
To find the mole ratio, we must use the coefficients.
[tex]P_4+6Br_2 \rightarrow 4PBr_3[/tex]
This equation is balanced (4 atoms of P and 12 atoms of Br on both sides), so we can go straight to the coefficients.
- P₄ doesn't have a coefficient, so 1 is implied
- Br₂ has a coefficient of 6
- PBr₃ has a coefficient of 4
So according to the coefficients above, for every 1 mole of P₄ that is consumed, 4 moles of PBr₃ are produced. Therefore, the ratio is 1 mole P₄ to 4 moles of PBr₃.
