Let's analyze the reaction given:
[tex]\[ H_2Y^{-} + H_2Z^{-} \rightleftharpoons H_3Y + HZ^{2-} \][/tex]
We need to identify which species acts as an acid and which acts as a base in this reaction.
### Step-by-Step Analysis:
1. Identify the Proton Transfer:
- H[tex]\(_2Y^{-}\)[/tex] is changing to H[tex]\(_3Y\)[/tex]. This indicates that H[tex]\(_2Y^{-}\)[/tex] is gaining a proton (H[tex]\(^+\)[/tex]) to become H[tex]\(_3Y\)[/tex].
- H[tex]\(_2Z^{-}\)[/tex] is changing to HZ[tex]\(^{2-}\)[/tex]. This indicates that H[tex]\(_2Z^{-}\)[/tex] is losing a proton (H[tex]\(^+\)[/tex]) to become HZ[tex]\(^{2-}\)[/tex].
2. Determine the Acid and Base:
- An acid is a species that donates a proton in a reaction.
- A base is a species that accepts a proton in a reaction.
Given the definitions:
- H[tex]\(_2Z^{-}\)[/tex] donates a proton and thus acts as the acid.
- H[tex]\(_2Y^{-}\)[/tex] accepts a proton and thus acts as the base.
### Conclusion:
- H\[2Z^-] is the acid.
- H\[2Y^-] is the base.
Thus, based on the reaction and the definitions of acids and bases, our answer is:
- Acid: H[tex]\(_2Z^-\)[/tex]
- Base: H[tex]\(_2Y^-\)[/tex]
This comprehensively explains which species acts as an acid and which acts as a base in the given chemical reaction.
