To determine which of the given reactions involves a transfer of electrons, we need to look for redox reactions where oxidation states of atoms change, indicating that electrons are being transferred.
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PCl3 + Cl2 → PCl5
- In this reaction, phosphorus is oxidized from +3 in PCl3 to +5 in PCl5, and chlorine is reduced from 0 in Cl2 to -1 in PCl5. Therefore, this reaction involves a transfer of electrons.
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CO2 + 2LiOH → Li2CO3 + H2O
- This reaction does not involve a change in oxidation states of the elements involved; thus, it does not involve a transfer of electrons.
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FeCl2 + 2NaOH → Fe(OH)2 + 2NaCl
- In this reaction, iron remains in the +2 oxidation state throughout, thus there is no transfer of electrons.
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NaOH + HCl → NaCl + H2O
- This is an acid-base neutralization reaction. There are no changes in oxidation states, so no electrons are transferred.
Based on the analysis, the reaction that involves a transfer of electrons is:
PCl3 + Cl2 → PCl5.