Answered

Select the correct answer.

Which statement correctly relates two substances from this reaction?

[tex]\[ H_2CO_3 + H_2O \rightleftharpoons H_3O^+ + HCO_3^- \][/tex]

A. [tex]\( HCO_3^- \)[/tex] is the conjugate acid of [tex]\( H_2CO_3 \)[/tex].

B. [tex]\( H_2O \)[/tex] is the conjugate base of [tex]\( H_2CO_3 \)[/tex].

C. [tex]\( H_3O^+ \)[/tex] is the conjugate acid of [tex]\( H_2O \)[/tex].

D. [tex]\( H_2CO_3 \)[/tex] is the conjugate base of [tex]\( H_3O^+ \)[/tex].



Answer :

Certainly! Let's analyze the given chemical reaction step by step to understand which statement correctly relates two substances from this reaction.

The reaction given is:
[tex]\[ H_2CO_3 + H_2O \rightleftharpoons H_3O^+ + HCO_3^- \][/tex]

In this equation:
- [tex]\( H_2CO_3 \)[/tex] (Carbonic acid) is reacting with [tex]\( H_2O \)[/tex] (Water).
- The products of this reaction are [tex]\( H_3O^+ \)[/tex] (Hydronium ion) and [tex]\( HCO_3^- \)[/tex] (Bicarbonate ion).

To understand the relationship between the substances, let's define the terms conjugate acid and conjugate base:
1. Conjugate Acid: The species formed when a base gains a proton (H+).
2. Conjugate Base: The species formed when an acid loses a proton (H+).

Now let’s analyze the possible options:
### A. [tex]\(HCO_3^-\)[/tex] is the conjugate acid of [tex]\(H_2CO_3\)[/tex].
- In reality, [tex]\( H_2CO_3 \)[/tex] loses a proton to form [tex]\( HCO_3^- \)[/tex]. So, [tex]\( HCO_3^- \)[/tex] is the conjugate base of [tex]\( H_2CO_3 \)[/tex], not the conjugate acid. Therefore, this statement is incorrect.

### B. [tex]\( H_2O \)[/tex] is the conjugate base of [tex]\( H_2CO_3 \)[/tex].
- Here, [tex]\( H_2CO_3 \)[/tex] loses a proton and forms [tex]\( HCO_3^- \)[/tex]. Water ([tex]\( H_2O \)[/tex]) acts as a base and accepts a proton to form [tex]\( H_3O^+ \)[/tex]. Therefore, [tex]\( H_2O \)[/tex] is not related as the conjugate base of [tex]\( H_2CO_3 \)[/tex]; it is the base that accepts a proton to become [tex]\( H_3O^+ \)[/tex]. This statement is also incorrect.

### C. [tex]\( H_3O^+ \)[/tex] is the conjugate acid of [tex]\( H_2O \)[/tex].
- In this case, [tex]\( H_2O \)[/tex] (water) accepts a proton (H+) to form [tex]\( H_3O^+ \)[/tex] (Hydronium ion). Thus, [tex]\( H_3O^+ \)[/tex] is indeed the conjugate acid of [tex]\( H_2O \)[/tex]. This statement is correct.

### D. [tex]\( H_2CO_3 \)[/tex] is the conjugate base of [tex]\( H_3O^+ \)[/tex].
- [tex]\( H_2CO_3 \)[/tex] is an acid that loses a proton to form [tex]\( HCO_3^- \)[/tex]. [tex]\( H_2CO_3 \)[/tex] is not formed from [tex]\( H_3O^+ \)[/tex], so [tex]\( H_2CO_3 \)[/tex] is not the conjugate base of [tex]\( H_3O^+ \)[/tex]. Hence, this statement is incorrect.

Based on the analysis above, the correct statement is:

C. [tex]\( H_3O^+ \)[/tex] is the conjugate acid of [tex]\( H_2O \)[/tex].