What is the hydronium ion concentration of a solution with a pOH of 7.20? A - 1.56 × 10^−6 M
B - 1.79 × 10^−6 M
C - 1.58 × 10^−7 M
D - 2.78 × 10^−7 M

I think the correct answer is C, can anyone confirm this?

C - 1.58 × 10^−7 M

Explanation:

The hydroxide ion concentration can be found from the pOH by the reverse mathematical operation employed to find the pOH. [OH-] = 10-pOH or [OH-] = antilog ( - pOH) Page 2 Example: What is the hydroxide ion concentration in a solution that has a pOH of 5.70? On a calculator calculate 10-5.70, or "inverse" log (- 5.70).

24.6kpa

Explanation:

This is a classic case where Boyle's Law can be applied.

The equation for Boyle's Law is given as: P1V1 = P2V2

Where P1 = initial pressure

P2 = final pressure

V1 = initial volume

V2 = final volume

From the question, P1 = ?, P2 = 98.2kpa , V1 =4L , V2 =1L

P1V1 = P2V2

P1 x 4L = 98.2 kpa x 1L

Make P1 subject of formula we then have:

P1 = 98.2kpa X 1L / 4L

= 24.6kpa