To find the pH of a solution when 10 mL of a 1 M HCl solution is added to 10 mL of a 1 M NaOH solution, follow these steps:
1. Determine the moles of HCl and NaOH:
- Volume of HCl = 10 mL
- Molarity of HCl = 1 M
- Volume of NaOH = 10 mL
- Molarity of NaOH = 1 M
To calculate the number of moles, use the formula:
[tex]\[
\text{moles} = \text{volume} \times \text{molarity} / 1000
\][/tex]
For HCl:
[tex]\[
\text{moles\_HCl} = 10 \, \text{mL} \times 1 \, \text{M} / 1000 = 0.01 \, \text{moles}
\][/tex]
For NaOH:
[tex]\[
\text{moles\_NaOH} = 10 \, \text{mL} \times 1 \, \text{M} / 1000 = 0.01 \, \text{moles}
\][/tex]
2. Compare the moles of HCl and NaOH:
- Moles of HCl = 0.01 moles
- Moles of NaOH = 0.01 moles
Since the moles of HCl and NaOH are equal, they will completely neutralize each other.
3. Determine the excess moles (if any):
- Here, there are no excess moles of either HCl or NaOH since they are in equal amounts.
4. Calculate the resulting pH:
- Since the amounts of HCl and NaOH are equal and they completely neutralize each other, the resulting solution will be neutral.
The pH of a neutral solution is 7.
Therefore, the pH of the solution when 10 mL of a 1 M HCl solution is added to 10 mL of a 1 M NaOH solution is [tex]\( \boxed{7} \)[/tex].
