Question

According to the Brønsted-Lowry theory, an acid is any substance (molecule or ion) that can transfer a proton (H+ ion) to another substance, and a base is any substance that can accept a proton. Acid-base reactions are proton-transfer reactions, as follows:

HA	+	B	⇌	BH+	+	A−
acid		base		acid		base

Chemical species whose formulas differ only by one proton are said to be conjugate acid-base pairs. Thus, A− is the conjugate base of the acid HA, and HA is the conjugate acid of the base A−. Similarly, B is the conjugate base of the acid BH+, and BH+ is the conjugate acid of the base B. The stronger the acid, the weaker the conjugate base, and the stronger the base, the weaker the conjugate acid.

Part B

What is the conjugate base of HSO4−?

Express your answer as a chemical formula.

Part C

What is the conjugate acid of HPO22− ?

Express your answer as a chemical formula.

Part D

Among three bases, X−, Y−, and Z−, the strongest one is Y−, and the weakest one is Z−. Rank their conjugate acids, HX, HY, and HZ, in order of decreasing strength.

Rank the acids from strongest to weakest. To rank items as equivalent, overlap them.

HX HZ HY Strongest acid Weakest acid

Answer 1

B) Conjugate base of HSO4- is SO ₄^2-.

C) Conjugate acid of HPO22- is H ₂PO₂^-.

D) Conjugate acid order is

HZ > HX > HY