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NDA2026General AbilityGeneral ScienceActual

Consider the following: I. AlCl ₃ II. NH ₃ III. BF ₃ IV. FeCl ₃ How many of the above are Lewis acids?

Options

  1. AOne
  2. BTwo
  3. CThree
  4. DAll the four

Correct answer

C. Three

Step-by-step solution

Lewis acids are chemical species that can accept a pair of electrons. They are typically electron-deficient molecules or cations with empty orbitals. AlCl ₃ has an incomplete octet (6 electrons around Al) and acts as a Lewis acid. NH ₃ has a lone pair of electrons on the nitrogen atom and acts as a Lewis base (electron pair donor). BF ₃ has an incomplete octet (6 electrons around B) and acts as a Lewis acid. FeCl ₃ has empty d-orbitals on the central iron atom, allowing it to accept electron pairs, thus acting as a

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