Arrange the following aqueous solutions, all at 25 ∘C, in order of decreasing acidity. Rank from most acidic to most basic. To rank items as equivalent, overlap them.

Rank from most acidic to most basic is

0.0023 M HCl pH = 5.45 and pOH = 8.55 0.0018 M KOH

Explanation:

This question is missing options.

Options are

pOH = 8.55 pH = 5.45 0.0023 M HCl 0.0018 M KOH

To rank these solutions first calculate either pH or pOH of these solutions.

We will use pH as an indicator to rank these.

Relation between pH and pOH is

pH + pOH = 14 ... Eq (A)

For pOH = 8.55

use equation A

pH + 8.55 = 14

pH = 5.45

For pH = 5.45

pH = 5.45

For 0.0023 M HCl

HCl is a strong acid. It will ionize 100% in aqueous solution and produce Hydronium Ion. Formula to calculate pH of 0.0023 M HCl is,

pH = - log (Molarity)

pH = - log (0.0023)

pH = - (-2.64)

pH = 2.64

For 0.0018 M KOH

KOH is a base. It will produce Hydroxide Ion in aqueous solution. First calculate pOH and convert it into pH.

pOH = - log (Molarity)

pOH = - log (0.0018)

pOH = 2.74

use equation A

pH + 2.74 = 14

pH = 11.26

Lower the pH more acidic the solution is. Rank from most acidic to most basic is

0.0023 M HCl pH = 5.45 and pOH = 8.55 0.0018 M KOH