Which of the following involves a transfer of electrons? pcl3 + cl2 → pcl5 co2 + 2lioh → li2co3 + h2o fecl2 + 2naoh → fe(oh)2 + 2nacl naoh + hcl → nacl + h2o

Answer is: PCl3 + Cl2 → PCl5.

Balanced chemical reaction: PCl₃ + Cl₂ → PCl₅.

Oxidation half reaction: P⁺³ → P⁺⁵ + 2e⁻.

Reduction half reaction: Cl₂ + 2e⁻  → 2Cl⁻.

In this chemical reaction phosphorus lost two electrons and change oxidatation number from +3 to +5; chlorine gain those two electrons and change oxidation number form 0 to -1.

In other chemical reactions, elements do not change oxidation numbers.

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2