Question

Identify the Lewis acids and Lewis bases in the following reactions:

Answer 1

Answer: 1. $H^++OH^-\rightarrow H_2O$  Lewis acid : $H^+$, Lewis base : $OH^-$

2. $Cl^-+BCl_3\rightarrow BCl_4^-$ Lewis acid : $BCl_3$, Lewis base : $Cl^-$

3. $K^++6H_2O\rightarrow K(H_2O)_6$ Lewis acid : $K^+$, Lewis base : $H_2O$

Explanation:

According to the Lewis concept, an acid is defined as a substance that accepts electron pairs and base is defined as a substance which donates electron pairs.

1. $H^++OH^-\rightarrow H_2O$

As $H^+$ gained electrons to complete its octet. Thus it acts as lewis acid.$OH^-$ acts as lewis base as it donates lone pair of electrons to electron deficient specie $H^+$.

2. $Cl^-+BCl_3\rightarrow BCl_4^-$

As $BCl_3$ is short of two electrons to complete its octet. Thus it acts as lewis acid. $Cl^-$ acts as lewis base as it donates lone pair of electrons to electron deficient specie $BCl_3$.

3. $K^++6H_2O\rightarrow K(H_2O)_6$

As $K^+$ is short of electrons to complete its octet. Thus it acts as lewis acid. $H_2O$ acts as lewis base as it donates lone pair of electrons to electron deficient specie $K^+$.