Question

(viii) Consider the following reaction? H2O + HCl -H30+ + Cl- Which species is an electron pair acceptor in this reaction? (a) H2O (b) HCI (C) H30+ (d) none​

Answer 1

Answer:

In the given question, HCl is an electron pair acceptor.

Explanation:

Electron pair donors are called Lewis bases or nucleophiles and electron pair acceptors are called as Lewis acids or electrophiles.

Lewis bases include negatively charged ions, molecules with lone pair( eg. NH₃) etc. while Lewis acids include positively charged ions or atoms with vacant d- orbitals or molecules which are electron deficient( eg. BF₃ ).

These can be easily confused with Bronsted bases and Bronsted acids.

Bronsted acids are proton donors and Bronsted bases are proton acceptors.

In the given equation, H₂0 and Cl⁻ are Bronsted bases as they take an H⁺ to form H₃O⁺ and HCl respectively. That makes hydronium ion and HCl Bronsted acids.

Here's one important point to note- Bronsted acids are not always Lewis acids but Bronsted bases are always Lewis bases( since a species must take a proton to donate an electron pair ).

Therefore, here, HCl is a Lewis acid and an electron pair acceptor but it is NOT a Bronsted acid.

[ Hope I helped clear the concept. ]