Question

sing the Brønsted-Lowry concept of acids and bases, identify the Brønsted-Lowry acid and base in each of the following reactions: HSO3−(aq)+H2O(l)→H2SO3(aq)+OH−(aq) (CH3)3N(g)+BCl3(g)→(CH3)3NBCl3(s)

Answer 1

Answer: a) $HSO_3^-$: Bronsted base

$H_2O$ : Bronsted acid

b) None

Explanation:

According to the Bronsted-Lowry conjugate acid-base theory, an acid is defined as a substance which looses donates protons and thus forming conjugate base and a base is defined as a substance which accepts protons and thus forming conjugate acid.

For the given chemical equations:

a) $HSO_3^-(aq.)+H_2O(l)\rightarrow H_2SO_3(aq.)+OH^-(aq.)$

Here, $HSO_3^-$ is accepting a proton, thus it is considered as a base and after gaining a proton, it forms $H_2SO_3$ which is an conjugate acid.

And, $H_2O$ is losing a proton, thus it is considered as a acid and after losing a proton, it forms $OH^-$ which is a conjugate base.

b) [tex[(CH_3)_3N(g)+BCl_3(g)\rightarrow (CH_3)_3NBCl_3(s)[/tex]

As there is no donation or acceptance of $H^+$, they cannot be considered as Bronsted acid or base. $(CH_3)_3N$ gives its electrons to $BCl_3$, thus $(CH_3)_3N$ act as lewis base and $BCl_3$ act as lewis acid.