Question

KHW27 Tro 14.9-14.10 (90 min) Exercise 14.108 Term 2: Significant Figures Feedback: Your answer 3.IU2 was either rounded differentiy number of significant figures than required for this part. Constants Perniodic Table For each strong base solution, determine OH HO] pH, and pOH PartG 3.5x10-4 M Ca(OH), determine [OH l and [H30] Express your answers using two significant figures. Enter your answers numerically separat [OH ] [H307 = 13.5 . I 0 4,2.9. 10-11 Submit Previous Answers Request Answer Incorrect; Try Again; 4 attempts remaining

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Answer 1

1. Given that [Ca(OH)₂] = 3.5 * 10^-4 M

1 mol of Ca(OH)₂ contains 2 mol of OH^-

So,[OH^-] = 2*3.5 * 10^-4 M = 7.0 *10^-4 M

Since , K_w = [H₃O⁺][OH^-] = 10^-14

[H₃O⁺] =  10^-14 /  7.0 *10^-4 M = 1.43 * 10^-11 M

2. Since, , K_w = [H₃O⁺][OH^-] = 10^-14

pH = -log[H₃O⁺]

Now, If pH > 7 then solution is acidic   

= 7 neutral

< 7 . basic

[OH-]	[H3o+]	pH
6 * 10-12	0.00167	2.78	Acidic
3*10-9	3.33 * 10-6	5.48	acidic
2*10-10	5 * 10-5	4.30	acidic
4 * 10-13	0.025	1.60	acidic
4 * 10-2	3 * 10-13	12.52	Basic
7 * 10-4	1.43 * 10-11	10.85	Basic
6 * 10-5	1.67 * 10-10	9.78	Basic
1* 10-7	1* 10-7	7	Neutral

3. [H₃O⁺] = 7.6*10^-5

K_w = [H₃O⁺][OH^-] = 10^-14

[OH^-] = 10^-14/ ( 7.6*10^-5) = 1.32 * 10^-10 M

4.[OH^-] = 1.5 *10^-2 M

K_w = [H₃O⁺][OH^-] = 10^-14

[H₃O⁺] =  10^-14 / ( 1.5 *10^-2 ) = 6.67 * 10^-13