21. Classify the following solutions in order of increasing pH:
a. 0.01 M NaOH
b. pure water
c. 0.10 M HCl
d. 0.05 M NaOH
e. 0.001 M HCl
Classify the following solutions in order of increasing pH:
0.01 M NaOH 3
pure water 2
0.10 M HCl 1
0.05 M NaOH
0.001 M HCl
To classify the solutions in order of increasing pH, we need to understand pH and how it is related to the concentration of hydrogen ions (H+) or hydroxide ions (OH-) in a solution.
pH is a measure of the acidity or basicity of a solution and ranges from 0 to 14. A pH value below 7 indicates acidity, while a pH value above 7 indicates alkalinity or basicity. A pH of 7 is considered neutral, such as pure water.
To determine the pH of a solution, we need to calculate the concentration of H+ or OH- ions. The lower the concentration of H+ ions, the higher the pH of the solution, and vice versa.
Now, let's classify the solutions in order of increasing pH:
1. Pure Water (b):
Pure water has a neutral pH of 7. This is because water dissociates into equal amounts of H+ and OH- ions, resulting in a balanced concentration of both ions.
2. 0.001 M HCl (e):
Hydrochloric acid (HCl) is a strong acid that dissociates completely in water. Since the concentration of H+ ions in the solution is higher compared to pure water, the pH of this solution will be lower than 7 (acidic).
3. 0.10 M HCl (c):
Similar to the previous solution, this is also hydrochloric acid but at a higher concentration. Consequently, the concentration of H+ ions is even higher, making the solution more acidic than 0.001 M HCl.
4. 0.05 M NaOH (d):
Sodium hydroxide (NaOH) is a strong base that dissociates completely in water. It releases OH- ions into the solution, resulting in increased OH- concentration and decreased H+ concentration. The higher OH- concentration results in a higher pH, making the solution more alkaline or basic.
5. 0.01 M NaOH (a):
This is another solution of sodium hydroxide but at a lower concentration. Compared to 0.05 M NaOH, the concentration of OH- ions is lower, leading to a slightly higher pH.
So, the solutions classified in increasing pH order are:
e. 0.001 M HCl
c. 0.10 M HCl
d. 0.05 M NaOH
a. 0.01 M NaOH
b. pure water