Consider the balanced chemical equation: PCl3 + Cl2 → PCl5. What is the mole ratio of PCl3 to PCl5 in this reaction?

• A. 5:3
• B. 2:1
• C. 1:1
• D. 3:5

Answer: (C)

Verified step by step guidance

1. Identify the balanced chemical equation given: \(\mathrm{PCl_3 + Cl_2 \rightarrow PCl_5}\).
2. Look at the coefficients in front of each compound in the balanced equation. Here, the coefficient for \(\mathrm{PCl_3}\) is 1 and for \(\mathrm{PCl_5}\) is also 1.
3. The mole ratio between two substances in a balanced chemical equation is the ratio of their coefficients.
4. Write the mole ratio of \(\mathrm{PCl_3}\) to \(\mathrm{PCl_5}\) as \$1:1$ because both have the coefficient 1.
5. This means that 1 mole of \(\mathrm{PCl_3}\) reacts to form 1 mole of \(\mathrm{PCl_5}\), confirming the mole ratio is \$1:1$.