This link might help you!!
https://www.eiu.edu/biology/bio1500/writing_a_lab_report.pdf
The definition of a Lewis acid and base is: Acid is any substance that can accept a pair of nonbonding electrons, while that a Base is a species that contains a nonbonding pair of electrons, and in the reaction in the question:
SO3 + H2O -> H2SO3 + 2 OH-
We have SO3 as the conjugate base of the acid H2SO3 and H2O is acting as an acid in this occasion, therefore the answer is Acid
The correct answer is D. The statement that no more than two electrons can occupy an atomic orbital and that two electrons in the same orbital must have opposite spins is from the Pauli Exclusion Principle. If one is in the +1/2 up-spin the other should be in the -1/2 down-spin. From this principle, no two electrons can have the same quantum numbers.
