1) DETERMINE pH of each of the following 2-component solutions.
0.08M RbOH & 0.130M NaHCO3
To determine the pH of a solution, we need to consider the dissociation of each compound and the resulting ions in the solution.
1) RbOH - RbOH dissociates into Rb+ and OH- ions. Since it is a strong base, it completely dissociates in water.
The concentration of OH- ions in the solution is 0.08 M.
2) NaHCO3 - NaHCO3 dissociates into Na+ and HCO3- ions. HCO3- is a weak base that can partially dissociate in water.
We need to consider the dissociation of HCO3- in water:
HCO3- + H2O ⇌ H2CO3 + OH-
H2CO3 ⇌ H+ + HCO3-
Since the concentration of NaHCO3 is 0.130 M, the concentration of HCO3- and OH- ions is also 0.130 M.
To determine the overall pH of the solution, we need to calculate the concentration of H+ ions in the solution.
The RbOH solution only has OH- ions, which are basic. The NaHCO3 solution has both OH- ions and HCO3- ions.
To find the concentration of H+ ions, we need to consider the reaction between OH- and H+ ions:
OH- + H+ ⇌ H2O
Since OH- is in excess in the solution, the reaction will proceed from right to left. Therefore, the concentration of H+ ions will be determined by the amount of OH- ions present in the solution.
In this case, the OH- concentration in the RbOH solution is 0.08 M, while in the NaHCO3 solution, it is 0.130 M.
To find the overall OH- concentration, we can add the concentrations from both solutions:
Overall OH- concentration = 0.08 M + 0.130 M = 0.210 M
Since OH- and H+ ions react to form water, the concentration of H+ ions in the solution will be equal to the OH- concentration.
Therefore, the concentration of H+ ions in the solution is 0.210 M.
To calculate the pH of the solution, we can use the formula:
pH = -log[H+]
Using the concentration of H+ ions, we can calculate the pH:
pH = -log(0.210) ≈ 0.68
To determine the pH of each of the following 2-component solutions (0.08M RbOH and 0.130M NaHCO3), we need to understand the concept of pH and the dissociation properties of the given compounds.
Step 1: Understand pH
pH is a measure of the acidity or alkalinity of a solution on a logarithmic scale. It ranges from 0 to 14, where pH 7 is considered neutral, pH less than 7 is acidic, and pH greater than 7 is alkaline or basic.
Step 2: Dissociation of RbOH
RbOH is an ionic compound that dissociates into Rb+ (rubidium ion) and OH- (hydroxide ion) in water. Since OH- is a strong base, it will increase the concentration of hydroxide ions in the solution and make it basic.
Step 3: Dissociation of NaHCO3
NaHCO3 is also an ionic compound that can dissociate into Na+ (sodium ion), HCO3- (bicarbonate ion), and OH- (hydroxide ion) in water. However, the dissociation of NaHCO3 is more complex. It primarily dissociates into Na+ and HCO3-. The HCO3- ion can further react with water to form H2CO3 (carbonic acid), which then dissociates into H+ (hydronium ion) and HCO3-. Therefore, NaHCO3 can be considered as a weak acid.
Step 4: Calculate pH for each solution
To calculate the pH for each solution, we need to consider the concentration of hydroxide ions (OH-) and hydronium ions (H+).
For 0.08M RbOH:
Since RbOH dissociates into OH- ions, we need to calculate the concentration of OH- ions. In this case, the concentration of OH- ions is also 0.08M.
pOH = -log[OH-]
pOH = -log(0.08)
pOH = 1.10
pH = 14 - pOH
pH = 14 - 1.10
pH = 12.90
Therefore, the pH of 0.08M RbOH solution is approximately 12.90, which indicates that it is strongly basic.
For 0.130M NaHCO3:
NaHCO3 can be considered as a weak acid, so we need to calculate the concentration of H+ ions resulting from the dissociation of HCO3-. The concentration of H+ ions can be assumed to be equal to the concentration of HCO3-.
pH = -log[H+]
pH = -log(0.130)
pH = 0.89
Therefore, the pH of 0.130M NaHCO3 solution is approximately 0.89, which indicates that it is slightly acidic.