Which of the following 0.10 M aqueous solutions
gives the LOWEST pH?
1. CH3COOH (pKa = 4.75)
2. CCl3COOH (pKa = 0.52)
3. HF (pKa = 3.45)
4. H3PO4 (pKa1 = 2.12)
5. Because all are acids, the pH is the same
for all solutions
To determine which of these solutions has the lowest pH, we need to compare the acidity (strength) of the acids. The lower the pKa value, the stronger the acid.
Let's analyze each of the options:
1. CH3COOH (pKa = 4.75)
2. CCl3COOH (pKa = 0.52)
3. HF (pKa = 3.45)
4. H3PO4 (pKa1 = 2.12)
Since we are looking for the solution with the lowest pH, we need to choose the acid with the lowest pKa value.
From the given options, CCl3COOH has the lowest pKa value of 0.52. Therefore, the solution of CCl3COOH will have the lowest pH among the given options.
To determine which of the given 0.10 M aqueous solutions has the lowest pH, you need to consider the pKa values of the acids.
The pKa value represents the acidity or the tendency of an acid to donate a proton (H+). The lower the pKa value, the stronger the acid.
In this case, you have five different acids with their respective pKa values. The one with the lowest pKa will have the highest acidity and, therefore, the lowest pH.
Let's compare the pKa values of the given acids:
1. CH3COOH (pKa = 4.75)
2. CCl3COOH (pKa = 0.52)
3. HF (pKa = 3.45)
4. H3PO4 (pKa1 = 2.12)
From the given values, we can see that CCl3COOH has the lowest pKa value (0.52). Therefore, CCl3COOH is the strongest acid among the options and will have the lowest pH when dissolved in water.
Thus, the answer is 2. CCl3COOH (pKa = 0.52).