. What is the pH of a solution in which 15 mL of 0.10 M NaOH is added to 25 mL of 0.10
M HCl?
moles NaOH=.015*.1=.0015moles
Moles HCl=.025*.1=.0025 moles
excess acid= .0010 moles
concentration=.0010/.040 moles/liter
pH=-log(H+)=-log(.025)=1.60 pretty acidic
Well, if NaOH and HCl are going to party together, they're going to make some water (H2O) and have a good laugh. But before they can do that, we need to figure out the pH of their solution.
First, let's find out how many moles of NaOH and HCl we have:
moles of NaOH = volume (L) x concentration (M) = 0.015 L x 0.10 M = 0.0015 moles
moles of HCl = volume (L) x concentration (M) = 0.025 L x 0.10 M = 0.0025 moles
Since NaOH and HCl react in a 1:1 ratio (they both have one mole of hydroxide (OH-) and hydrogen (H+) ions, respectively), they completely neutralize each other.
So, the limiting reactant is NaOH, which means all of it is used up. This leaves us with 0.0015 moles of OH-.
To find the concentration of OH- ions, we divide the moles of OH- by the total volume of the solution:
concentration (M) = moles of OH- / total volume (L) = 0.0015 moles / 0.040 L = 0.0375 M
Now, to find the pOH, we take the negative logarithm (base 10) of the OH- concentration:
pOH = -log(0.0375) ≈ 1.4
Finally, to find the pH, we subtract the pOH from 14 (pH + pOH = 14):
pH = 14 - 1.4 = 12.6
So, the pH of the solution is approximately 12.6. Laughter guaranteed!
To find the pH of the solution, we need to consider the balanced chemical equation for the reaction between NaOH and HCl:
NaOH + HCl → NaCl + H2O
Since NaOH is a strong base and HCl is a strong acid, they will react completely to form NaCl (a salt) and water (H2O). This means that the concentration of the resulting NaCl will be equal to the initial concentrations of NaOH and HCl.
Step 1: Calculate the moles of NaOH and HCl:
Moles of NaOH = concentration of NaOH x volume of NaOH = 0.10 M x 0.015 L = 0.0015 moles
Moles of HCl = concentration of HCl x volume of HCl = 0.10 M x 0.025 L = 0.0025 moles
Step 2: Determine the limiting reactant:
To determine the limiting reactant, we compare the moles of NaOH and HCl. The reaction will proceed until one of the reactants is completely consumed. The reactant with fewer moles is the limiting reactant.
Here, NaOH has fewer moles (0.0015 moles) compared to HCl (0.0025 moles). Therefore, NaOH is the limiting reactant.
Step 3: Calculate the remaining moles of HCl:
Since NaOH is the limiting reactant, all of it will react to form NaCl. This means that all the moles of NaOH will react with an equal number of moles of HCl. Therefore, the remaining moles of HCl will be:
Remaining moles of HCl = moles of HCl - moles of NaOH = 0.0025 moles - 0.0015 moles = 0.0010 moles
Step 4: Calculate the concentration of HCl in the final solution:
To calculate the concentration of HCl in the final solution, we need to consider the total volume of the solution after mixing.
Total volume of the solution = volume of NaOH + volume of HCl = 0.015 L + 0.025 L = 0.040 L
Concentration of HCl in the final solution = remaining moles of HCl / total volume of the solution = 0.0010 moles / 0.040 L = 0.025 M
Finally, to find the pH value of the solution, we can use the equation:
pH = -log[H+]
where [H+] is the concentration of hydrogen ions (H+), which is equal to the concentration of HCl in this case.
pH = -log(0.025) ≈ 1.60
Therefore, the pH of the solution is approximately 1.60.
To find the pH of the solution after mixing NaOH and HCl, we need to determine the concentration of the resulting solution.
First, we need to calculate the number of moles of NaOH and HCl. The number of moles can be calculated using the formula:
moles = concentration (M) x volume (L)
For NaOH:
moles of NaOH = 0.10 M x 0.015 L = 0.0015 mol
For HCl:
moles of HCl = 0.10 M x 0.025 L = 0.0025 mol
Since NaOH and HCl react in a 1:1 ratio to form water and NaCl, the number of moles of NaOH and HCl is the same. In this case, the limiting reagent is NaOH because it is in lesser quantity.
Now that we know the number of moles, we can calculate the concentration of the resulting solution by dividing the total moles by the total volume of the solution.
Total moles of NaOH + HCl = 0.0015 mol + 0.0025 mol = 0.004 mol
Total volume of the solution = 0.015 L + 0.025 L = 0.04 L
Concentration of the resulting solution = 0.004 mol / 0.04 L = 0.1 M
Finally, we can find the pH of the solution. The pH scale is a measure of how acidic or basic a solution is. It is defined as the negative logarithm (base 10) of the hydrogen ion concentration.
pH = -log[H+]
Since the resulting solution is a neutralization reaction between NaOH (a strong base) and HCl (a strong acid), the amount of H+ ions and OH- ions will be equal, resulting in a neutral solution. Therefore, the pH will be 7.
So, the pH of the resulting solution is 7.