Question

Observe the following species: (i) \( NH_3 \) (ii) \( AlCl_3 \) (iii) \( SnCl_4 \) (iv) \( CO_2 \) (v) \( Ag^+ \) (vi) \( HSO_4^- \) How many of the above species act as Lewis acids?

• A. 5
• B. 3
• C. 4
• D. 2
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Hint:

A Lewis acid is an electron pair acceptor. Look for species with vacant orbitals or positive charges.

Answer 1

The Correct Option is C

Step 1: Understanding Lewis Acids
A Lewis acid is a species that can accept a pair of electrons. Step 2: Identifying Lewis Acids
- \( NH_3 \) (Ammonia): Lewis base (donates lone pair).
- \( AlCl_3 \) (Aluminum chloride): Lewis acid (electron-deficient central atom).
- \( SnCl_4 \) (Tin chloride): Lewis acid (electron-deficient central atom).
- \( CO_2 \) (Carbon dioxide): Lewis acid (can accept electrons due to vacant orbitals).
- \( Ag^+ \) (Silver ion): Lewis acid (accepts lone pair).
- \( HSO_4^- \) (Bisulfate ion): Not a strong Lewis acid. Thus, the Lewis acids are \( AlCl_3, SnCl_4, CO_2, Ag^+ \) (4 species). \bigskip