Question

Which molecule is considered a base in the Lewis model, but not in the Brønsted-Lowry or Arrhenius model?
A) PO4^3-
B) NaOH
C) NH3
D) Na2S
the numbers that aren't after ^ are subscript. i couldn't make the numbers a smaller font or any indicator of it. sry

Answer 1

H is 99% of the time the sign of acids and OH which comes at the end is 99% of the time the sign of bases.

Answer 2

Now look at your choices and see which one is the base with OH sign at the end.

Answer 3

Not 99% of the time. What about CH3CO-OH? ?? That's an acid.
There's also Et-OH is an acid. a weak one, but an acid, still.