Question

4. Circle all the pairs of compounds below that represent a conjugate acid base pair.

a. H2S/HS-
b. H3PO4/KH2PO4
c. Ca(OH)2/CaSO4
d. CH3CO2H/NaCH3CO2

Answer 1

Answer : The correct options are:

(a) H₂S/HS⁻

(b) H₃PO₄/KH₂PO₄

(d) CH₃CO₂H/NaCH₃CO₂

Explanation :

According to the Bronsted Lowry concept, Bronsted Lowry-acid is a substance that donates one or more hydrogen ion in a reaction and Bronsted Lowry-base is a substance that accepts one or more hydrogen ion in a reaction.

Or we can say that, conjugate acid is proton donor and conjugate base is proton acceptor.

The general equilibrium reaction will be,

`HA+B\rightleftharpoons BH^++A^-`

In this reaction,
`HA` is an acid that donate a proton or hydrogen to
`B` base and it forms
`A^-` and
`BH^+` are conjugate base and acid respectively.

That means,
`HA` and
`A^-` are conjugate acid base pair and
`B` and
`BH^+` are conjugate base acid pair.

(a) H₂S/HS⁻

This pair of compound represent a conjugate acid base pair.

(b) H₃PO₄/KH₂PO₄

This pair of compound represent a conjugate acid base pair.

(c) Ca(OH)₂/CaSO₄

This pair of compound does not represent a conjugate acid base pair because Ca(OH)₂ is strong base, it can accept a proton from conjugate acid.

(d) CH₃CO₂H/NaCH₃CO₂

This pair of compound represent a conjugate acid base pair.

Answer 2

The correct answer is a H2S/HS-

Step-by-step explanation:

H2S/HS- is a conjugate acid base pair because H2S is the conjugate acid as it has the ability to donate proton and according to the Arrhenius law we all know that that substance that can donate proton is called acid.Whereas HS- is the conjugate base .