Question

This formula equation is unbalanced.

P4(s) + 6Cl2(g) Right arrow. PCl3(l)

Which coefficient should be placed in front of PCl3 to balance this equation?
1
2
4
6

Answer 1

4

Explanation: P4 has 4 phosphorus atoms, so you need 4 PCl3 molecules (4 P atoms). Then 4 PCl3 contains 12 Cl atoms, which matches 6 Cl2 (6 × 2 = 12).