10mL of 0.10M HCl is given. What is the pH? How many milliliters of 0.10M NaOH would be required to neutralize it? What is the pH of the neutralized solution? What would the pH of the solution be if you added 20mL of NaOH?
Here's what I have so far:
pH of HCl=-log(0.10M)= 1
HCl + NaOH --> NaCl + H2O
C1*V1=C2*V2
(0.10M)V1=(0.10M)(0.010L)
V1=0.010L=10mL of 0.10M NaOH
The pH of neutralized solution would be 7 because NaCl is a salt from a strong base and strong acid, and NaCl in water has a neutral pH which is 7.
Thank you in advance!
All of these are correct. Make sure you understand the use of C1V1 = C2V2. That works ONLY when the ratio of acid to base is 1:1 as in the case of HCl and NaOH. It will not work for other cases. For example, it will not work for
H2SO4 + 2NaOH ==> Na2SO4 + 2H2O.
If we have 20 mL H2SO4 and titrate it with 20 mL of 0.1M NaOH, then concn H2SO4 is done as follows:
moles NaOH = M x L = 0.1M x 0.02 L = 0.002 moles NaOH.
Then convert moles NaOH to moles H2SO4. From the equation, 0.002 moles NaOH = 0.002/2 = 0.001 mole H2SO4.
Then M H2SO4 = mol H2SO4/L H2SO4 = 0.001mol/0.02L = 0.05M H2SO4.
You're on the right track with your calculations so far!
To determine the pH of 10mL of 0.10M HCl, you correctly use the formula pH = -log([H+]), where [H+] represents the concentration of hydrogen ions. Given that the concentration of HCl is 0.10M, you substitute the value into the formula and calculate:
pH = -log(0.10) = 1
So the pH of the 10mL 0.10M HCl solution is 1.
To determine the volume of 0.10M NaOH needed to neutralize the given amount of HCl, you can use the stoichiometry and concentration relationship defined by the balanced equation:
HCl + NaOH --> NaCl + H2O
You correctly set up the equation (C1*V1 = C2*V2), where C represents concentration and V represents volume. You are given that the concentration (C2) of NaOH is 0.10M. You want to find the volume (V1) of NaOH needed to neutralize the HCl, which has a concentration (C1) of 0.10M and a volume (V2) of 0.010L (which is equivalent to 10mL).
Using the equation, you can solve for V1:
(0.10M)V1 = (0.10M)(0.010L)
V1 = 0.010L = 10mL
So 10mL of 0.10M NaOH would be required to neutralize the given 10mL of 0.10M HCl.
The pH of the neutralized solution, which now contains NaCl, would be 7. This is because NaCl is a salt formed from a strong acid (HCl) and a strong base (NaOH). When a salt is dissolved in water, it undergoes hydrolysis, resulting in a solution with a pH equal to 7 (neutral pH).
Now, if you were to add an additional 20mL of NaOH to the neutralized solution, you would be increasing the concentration of the base in the solution. Since NaOH is a strong base, it dissociates completely in water, providing OH- ions. The addition of 20mL of NaOH would increase the hydroxide ion concentration in the solution. To determine the resulting pH, you would need to calculate the concentration of OH- ions after the addition, and then use the relationship between [OH-] and [H+] in water to derive the pH.
You're on the right track with your calculations!
1. The pH of 0.10M HCl is indeed 1. HCl is a strong acid, so it completely dissociates in water to produce H+ ions.
2. To neutralize the 10mL of 0.10M HCl, you correctly used the equation C1V1 = C2V2. Since the concentration (C2) of NaOH is the same as that of HCl, you need to solve for V1, which represents the volume of NaOH needed to neutralize the HCl. Plugging in the values, you get (0.10M)(V1) = (0.10M)(0.010L), which gives V1 = 0.010L or 10mL. Therefore, 10mL of 0.10M NaOH is required to neutralize the HCl.
3. The pH of the neutralized solution is not necessarily 7. While NaCl is a salt produced from a strong acid (HCl) and strong base (NaOH), it can still undergo hydrolysis in water. If the resulting hydrolysis creates an acidic or basic solution, the pH will deviate from 7. In this case, because equal volumes of equal concentrations of HCl and NaOH are used, the resulting solution will likely be close to neutral, but not exactly pH 7.
4. If you add 20mL of NaOH to the initial solution (which contains 10mL of HCl), the reaction will result in an excess of NaOH. Since there is more base than acid, the solution will become basic. To determine the specific pH of this new solution, you would need the concentrations of both HCl and NaOH, as well as the volumes added. However, if the initial concentration of NaOH is still 0.10M, and you add an equal volume of 20mL, the pH of the solution would likely be beyond pH 7 and become more basic compared to the neutralized solution.
Keep in mind that pH calculations can become more complex when dealing with excess reagents or other factors like dilution.