200 ml of 0.1 M sodium hydroxide is mixed with 100 ml of 0.2 M ethanoic acid. What is the pH of the resulting solution?
The alkali neutralises the acid:
The moles reacting (n) of each species is given by:
This shows that they are added in the same mole ratio as defined by the equation.
We can, therefore, say that the no. moles of
A salt formed from a weak acid and a strong base is slightly alkaline due to hydrolysis:
From an ICE table we can use this expression which applies to a weak base:
The total volume is now 200 ml + 100 ml = 300 ml = 0.3 L
You need to look up the
Putting in the numbers:
As expected the solution is slightly alkaline, even though the acid and base have been added in the same molar ratio.
This is really a two-part question:
- What is in the mixture after the reaction is complete?
- What is the
#"pH"#of the mixture?
What's in the mixture?
I like to use an ICE table to keep track of the stoichiometry calculations.
We have 300 mL of a solution that contains 0.020 mol of
2. What's the
The solution will be basic.
Now, we set up another ICE table (with molarities) to calculate the