Question

The hydronium ion concentration of your gastric fluid is 1.0 x 10^-2. you drink a tablespoon of milk of magnesia, which raises the ph of the fluid by one unit. what is the resulting concentration of hydroxide ions in the fluid

Answer 1

Answer:

1 × 10^-11 units.

Explanation:

Given:

[H+] = 1 × 10^-2

pH = - log [H+]

= -log [1 × 10^-2]

= 2

The question further said, "which raises the ph of the fluid by one unit"

pH(new) = 2 + 1

= 3

pH + pOH = 14

pOH = 14 - 3

= 11

pOH = - log [OH-]

[OH-] = 10^-11

= 1 × 10^-11 units

Answer 2

Answer:

[OH⁻] = 1 × 10⁻¹¹ mol/dm³

Explanation:

Since the hydronium ion concentration of the gastric fluid is [H₃O]⁺ = 1.0 × 10⁻².

The pH at this point is pH = -log₁₀[H₃O]⁺ = -log₁₀[1.0 × 10⁻²] = 2

When milk of magnesia is added, the pH increases by one unit, so the new pH is 1 + 2 = 3

Since pH + pOH = 14, then pOH = 14 - pH = 14 - 3 = 11

The hydroxide ion concentration of the fluid is gotten from

pOH = -log₁₀[OH⁻]

11 = -log₁₀[OH⁻]

-11 = log₁₀[OH⁻]

taking antilog

[OH⁻] = 1 × 10⁻¹¹ mol/dm³