To determine the conjugate acid-base pairs among the given species, we need to understand the concept of conjugate acids and bases.
Conjugate acid-base pairs are two species that differ by one proton (H+). When a substance donates a proton, it becomes its conjugate base, and when a substance accepts a proton, it becomes its conjugate acid.
Now let's analyze each option:
a. HS-4-, SO4^2-
To identify the conjugate acid-base pair, we need to find the one species that can donate a proton (acid) and the other species that can accept a proton (base).
In this case, HS-4- can donate a proton (HS-4- can lose one of its hydrogen ions to become HSO4-), and SO4^2- can accept the proton, becoming HSO4-. Therefore, HS-4- and HSO4- form a conjugate acid-base pair.
b. HBr, BrO-
To identify the conjugate acid-base pair, we need to find the one species that can donate a proton (acid) and the other species that can accept a proton (base).
In this case, HBr can donate a proton (HBr can lose one of its hydrogen ions to become Br-), and BrO- can accept the proton, becoming HBrO. However, Br- and BrO- are not a conjugate acid-base pair because they differ by two protons. Therefore, no conjugate acid-base pair exists for this option.
c. H2PO4-, PO4^3-
To identify the conjugate acid-base pair, we need to find the one species that can donate a proton (acid) and the other species that can accept a proton (base).
In this case, H2PO4- can donate a proton (H2PO4- can lose one of its hydrogen ions to become HPO4^2-), and PO4^3- can accept the proton, becoming HPO4^2-. Therefore, H2PO4- and HPO4^2- form a conjugate acid-base pair.
d. HNO3, NO2-
To identify the conjugate acid-base pair, we need to find the one species that can donate a proton (acid) and the other species that can accept a proton (base).
In this case, HNO3 can donate a proton (HNO3 can lose one of its hydrogen ions to become NO3-), and NO2- can accept the proton, becoming HNO2. Therefore, HNO3 and HNO2 form a conjugate acid-base pair.
In summary, the conjugate acid-base pairs are:
a. HS-4-, HSO4-
c. H2PO4-, HPO4^2-
d. HNO3, HNO2