Three bottles are labelled as shown:

Question

Bottle 1 0.001 mol/L HCl(aq)
Bottle 2 0.003 mol/L HBr(aq)
Bottle 3 0.002 mol/L KOH(aq)

Arrange the bottles in order of decreasing pH.
a) Bottle 3 > Bottle 1 > Bottle 2
b) Bottle 2 > Bottle 1 > Bottle 3
c) Bottle 1 > Bottle 2 > Bottle 3
d) Bottle 3 > Bottle 2 > Bottle 1
e) Bottle 2 > Bottle 3 > Bottle 1

Answer 1

To determine the order of decreasing pH, we need to consider the acidic or basic nature of the solutions. HCl is a strong acid, and HBr is also a strong acid. KOH is a strong base.

Since the pH is a measure of the concentration of H+ ions in a solution, a higher concentration of H+ ions corresponds to a lower pH.
Thus, the order of decreasing pH is:

b) Bottle 2 > Bottle 1 > Bottle 3

Answer 2

are you sure?

Answer 3

Apologies for the confusion. I made an error in my previous response.

To determine the order of decreasing pH, we need to consider the concentration of H+ ions in the solutions. The higher the concentration of H+ ions, the lower the pH.

HCl is a strong acid, meaning it dissociates completely in water to produce H+ ions. Therefore, the concentration of H+ ions in Bottle 1 is 0.001 mol/L, making it the highest concentration of H+ ions among the three bottles.

HBr is also a strong acid, so the concentration of H+ ions in Bottle 2 is 0.003 mol/L. This is higher than the concentration in Bottle 3.

KOH is a strong base and produces OH- ions when dissolved in water. Therefore, Bottle 3 is basic, and the concentration of H+ ions is low compared to Bottles 1 and 2.

Based on this information, the correct order of decreasing pH is:

c) Bottle 1 > Bottle 2 > Bottle 3

Answer 4

What is the correct answer?

Answer 5

I apologize for the confusion. The correct answer is:

d) Bottle 3 > Bottle 2 > Bottle 1