What is the correct assignment of the acid, base, conjugate acid and conjugate base in the following equilibrium?
A)1 = acid; 2 = base; 3 = conjugate acid; 4 = conjugate base
B)1 = acid; 2 = base; 3 = conjugate base; 4 = conjugate acid
C)1 = base; 2 = acid; 3 = conjugate acid; 4 = conjugate base
D)1 = base; 2 = acid; 3 = conjugate base; 4 = conjugate acid

Question

What is the correct assignment of the acid, base, conjugate acid and conjugate base in the following equilibrium? 
A)1 = acid; 2 = base; 3 = conjugate acid; 4 = conjugate base 
B)1 = acid; 2 = base; 3 = conjugate base; 4 = conjugate acid 
C)1 = base; 2 = acid; 3 = conjugate acid; 4 = conjugate base 
D)1 = base; 2 = acid; 3 = conjugate base; 4 = conjugate acid

Quizplus · Accepted Answer

In the given equilibrium, H2CO3 can donate a proton and acts as an acid, while HCO3^- can accept a proton and acts as a base. 
So, H2CO3 is the acid (1), HCO3^- is the base (2), HCO3^- is the conjugate base (3), and H2CO3 is the conjugate acid (4). 
Therefore, the correct assignment of acid, base, conjugate acid, and conjugate base is 1 = acid; 2 = base; 3 = conjugate base; 4 = conjugate acid. Choice B is the correct answer.

What Is the Correct Assignment of the Acid, Base, Conjugate