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.
Step-by-step explanation:
1) In saturated lime water, [H⁺] = 3.98 x 10⁻¹³ M.
a) Find [OH⁻]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(3.98 x 10⁻¹³ M) = 0.025 M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.98 x 10⁻¹³ M.
∴ pH = - log(3.98 x 10⁻¹³ M) = 12.4.
c) Is the solution acidic, basic, or neutral?
- 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.
∴ The solution is basic.
2) In butter, [H⁺] = 6.0 x 10⁻⁷ M.
a) Find [OH⁻]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [OH⁻] = 10⁻¹⁴/[H⁺] = 10⁻¹⁴/(6.0 x 10⁻⁷ M) = 1.66 x 10⁻⁸ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 6.0 x 10⁻⁷ M.
∴ pH = - log(6.0 x 10⁻⁷ M) = 6.22.
c) Is the solution acidic, basic, or neutral?
- 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.
∴ The solution is acidic.
3) In peaches, [OH⁻] = 3.16 x 10⁻¹¹ M
a) Find [H⁺]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻¹¹ M) = 3.16 x 10⁻⁴ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁴ M.
∴ pH = - log(3.16 x 10⁻⁴ M) = 3.5.
c) Is the solution acidic, basic, or neutral?
- 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.
∴ The solution is acidic.
4) During the course of the day, human saliva varies between being acidic and basic. If [OH⁻] = 3.16 x 10⁻⁸ M,
a) Find [H⁺]
∵ [H⁺][OH⁻] = 10⁻¹⁴.
∴ [H⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.16 x 10⁻⁸ M) = 3.16 x 10⁻⁷ M.
b) What is the pH?
∵ pH = - log[H⁺].
[H⁺] = 3.16 x 10⁻⁷ M.
∴ pH = - log(3.16 x 10⁻⁷ M) = 6.5.
c) Is the solution acidic, basic, or neutral?
- 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.
∴ The solution is acidic.