What is the molarity of 555 L of a Ba(OH)2
solution if the pH is 10.20?
1. 4.40 × 10−2 M
2. 3.14 × 10−4 M
3. 1.58 × 10−4 M
4. 3.15 × 10−11 M
5. 6.31 × 10−11 M
6. 2.26 × 10−5 M
7. 7.92 × 10−5 M
8. 5.15 × 10−7 M
1 Answer
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pH + pOH = 14.00.
pOH = 14.00 – pH = 14.00 – 10.20 = 3.80.
[OH-] = 10^-pOH = 10^-3.80 = 1.58 x 10^-4 M
In the formula Ba(OH)2, there are 2 moles of OH- for every 1 mole of Ba(OH)2.
(1.58 x 10^-4 moles OH- / L) x (1 mole Ba(OH)2 / 2 moles OH-) = 7.92 x 10^-5 M Ba(OH)2
CHOICE 7