Identify the acid, base, conjugate acid and conjugate base in the given reactions

Identify the acid, base, conjugate acid and conjugate base for the following reactions:

a)   HClO4(aq) + H2O(l) ⇄H3O+(aq) + ClO4–(aq)

b)   H2SO3(aq) + H2O(l) ⇄H3O+(aq) + HSO3–(aq)

c)   HC2H3O2(aq) + H2O(l) ⇄H3O+(aq) + C2H3O2–(aq)

Answer : Any reaction is which a proton trasfer takes place from one substance to another is an acid-base reaction.More specifially the proton transfer view is know as the bronsted-lowry defincation of acids and base.

In an acid-base reaction:

An Acid : donates a proton .So, any substance that gives up the proton to another substance is an acid.

A base : accepts a proton from anoother substance . Any substance that accepts a proton from another substance is a base.

a) HClO4(aq) + H2O(l) ⇄H3O+(aq) + ClO4–(aq)

In this equation we see that HClO4 has donated a proton to H2O so HClO4 is acting as an acid and as H2O is accepting a proton so H2O is a base.ClO4- on the other can accept a proton so ClO4- is a base but its a conjugate base to acid HClO4 since it is generatd by losing a proton from HClO4 .Similary, H3O+ is an acid but it is a conjugate acid as it has the capacity to donate a proton but it is a conjugate acid of base H2O as it has been generated by accepting a proton from H2O.

HClO4(aq) + H2O(l) ⇄   H3O+(aq) +   ClO4–(aq)

acid                base          conj.acid         conj.base

 B) H2SO3(aq) + H2O(l) ⇄H3O+(aq)   + HSO3–(aq)

       acid                 base          conj.acid     conj base

  As explained above H2SO3 is an acid since it has donated a proton and H20 is a base since it has accepted a proton and HSO3- is a conjugate base to acid H2SO3 and H3O+ is a conj.acid to base H2O.

c)  HC2H3O2(aq) + H2O(l) ⇄H3O+(aq) + C2H3O2–(aq)

     acid                        base      conj.acid       conj.base