Amongst the given options which of the following molecules/ion acts as a Lewis acid?
- H2O
- BF3
- OH-
- NH3
Answer
(2) BF3
Solution
A Lewis acid accepts an electron pair.
In BF3, boron has only 6 electrons in its valence shell (electron deficient), so it accepts a lone pair, e.g. BF3 + :NH3 F3B NH3.
H2O, OH- and NH3 have lone pairs to donate, so they act as Lewis bases.
Answer: (2)