Final answer:
The Lewis bases among the options are H₂O (water) and PCl₃ (phosphorus trichloride), which can donate a pair of electrons, making option E (both a and b) the correct answer.
Step-by-step explanation:
The question asks which of the given options could act as a Lewis base. Lewis bases are species that can donate a pair of electrons to form a covalent bond. Among the options:
- H₂O (water) is a common Lewis base because it has two lone pairs of electrons that can be donated.
- PCl₃ (phosphorus trichloride) can also act as a Lewis base since it has a lone pair of electrons on the phosphorus atom.
- Lu³⁺ (lutetium ion) is a Lewis acid as it can accept electrons.
- FeCl₃ (iron(III) chloride) is typically a Lewis acid as it can accept electrons due to empty d-orbitals on the iron.
Therefore, the Lewis bases in the options given are both H₂O and PCl₃, which are option E.