Answer:
1) a) [OH⁻] = 0.025 M.
b) pH = 12.4.
c) The solution is basic.
2) a) [OH⁻] = 1.66 x 10⁻⁸ M.
b) pH = 6.22.
c) The solution is acidic.
3) a) [H⁺] = 3.16 x 10⁻⁴ M.
b) pH = 3.5.
c) The solution is acidic.
4) a) [H⁺] = 3.16 x 10⁻⁷ M.
b) pH = 6.5.
c) The solution is acidic.
Explanation:
<em><u>1) In saturated lime water, [H⁺] = 3.98 x 10⁻¹³ M. </u></em>
<em><u>a) Find [OH⁻]</u></em>
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(3.98 x 10⁻¹³ M) = 0.025 M.
<u><em>b) What is the pH?</em></u>
∵ pH = - log[H⁺].
[H⁺] = 3.98 x 10⁻¹³ M.
∴ pH = - log(3.98 x 10⁻¹³ M) = 12.4.
<u><em>c) Is the solution acidic, basic, or neutral?</em></u>
- We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.
pH is a scale from 0 to 14.
- If pH < 7, the solution is acidic.
- If pH = 7, the solution is neutral.
- If pH > 7, the solution basic.
∵ pH = 12.4 > 7.
<em>∴ The solution is basic.</em>
<em></em>
<u><em>2) In butter, [H⁺] = 6.0 x 10⁻⁷ M. </em></u>
<u><em>a) Find [OH⁻]</em></u>
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(6.0 x 10⁻⁷ M) = 1.66 x 10⁻⁸ M.
<u><em>b) What is the pH?</em></u>
∵ pH = - log[H⁺].
[H⁺] = 6.0 x 10⁻⁷ M.
∴ pH = - log(6.0 x 10⁻⁷ M) = 6.22.
<u><em>c) Is the solution acidic, basic, or neutral?</em></u>
- We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.
pH is a scale from 0 to 14.
- If pH < 7, the solution is acidic.
- If pH = 7, the solution is neutral.
- If pH > 7, the solution basic.
∵ pH = 6.22 < 7.
<em>∴ The solution is acidic.</em>
<em />
<u><em>3) In peaches, [OH⁻] = 3.16 x 10⁻¹¹ M</em></u>
<u><em>a) Find [H⁺]</em></u>
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻¹¹ M) = 3.16 x 10⁻⁴ M.
<u><em>b) What is the pH?</em></u>
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁴ M.
∴ pH = - log(3.16 x 10⁻⁴ M) = 3.5.
<u><em>c) Is the solution acidic, basic, or neutral?</em></u>
- We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.
pH is a scale from 0 to 14.
- If pH < 7, the solution is acidic.
- If pH = 7, the solution is neutral.
- If pH > 7, the solution basic.
∵ pH = 3.5 < 7.
<em>∴ The solution is acidic.</em>
<em></em>
<u><em>4) During the course of the day, human saliva varies between being acidic and basic. If [OH⁻] = 3.16 x 10⁻⁸ M,</em></u>
<u><em>a) Find [H⁺]</em></u>
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻⁸ M) = 3.16 x 10⁻⁷ M.
<u><em>b) What is the pH?</em></u>
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁷ M.
∴ pH = - log(3.16 x 10⁻⁷ M) = 6.5.
<u><em>c) Is the solution acidic, basic, or neutral?</em></u>
- We can determine the nature of the solution, acidic, basic or neutral, from the value of the pH.
pH is a scale from 0 to 14.
- If pH < 7, the solution is acidic.
- If pH = 7, the solution is neutral.
- If pH > 7, the solution basic.
∵ pH = 6.5 < 7.
<em>∴ The solution is acidic.</em>
<em></em>