Determining the Highest pH for Acid Solutions

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In summary, the question is asking which of the given solutions, all at a concentration of 0.10 M at 25 C, would have the highest pH. This refers to the analytical concentration of the acid in the solution, which is the result of dissolving 0.1 moles of the acid in 1L of water. The pKa values are used to determine the pH of the solutions, with higher pKa values indicating a higher pH and lower acidity. This means that the solution of acetic acid, with a pKa of 4.756, will have a higher pH compared to the solution of oxalic acid, with a pKa of 1.27. Therefore, the acetic acid solution will
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sp3sp2sp
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Homework Statement


I am just a little confused about how the question is worded. It asks:
Which of the following solutions would have the highest pH? Assume that they are all
0.10 M in acid at 25 C
. The acid is followed by its Ka value.
the bolded is what I don't understand. I don't know what they mean by "in acid" ? thanks for any help

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That means the analytical cocentration of the acid is 0.10M. That is, the solution is the result of dissolving 0.1 moles of the acid in 1L of water. Actually, the acid will be partly dissociated, so the true concentration of the acid form will be less than 0.1 M. So if you had 0.1 moles of acetic acid (AcOH) in water, you would have some undissociated AcOH and some dissociated H+ and AcO-. The total concentration of AcOH and AcO- would be 0.1 M, and that is what the question refers to.
 
  • #3
The values for pKa come from the acids' Ka values. The "p" part of the constant means, "negative logarithm of...".

Two specific examples:
Acetic Acid, Ka=1.8*10^(-5), pKa=4.756, weak monoprotic acid
Oxalic Acid, Ka1=5.37*10^(-2), pKa1=1.27, diprotic acid, not so weak compared to Acetic

Each if dissolved to the same molarity will show less acidic for Acetic than for Oxalic; Meaning LOWER pH for Acetic than for the stronger Oxalic.
The Acetic Acid solution will have the higher pH, of the two solutions. You can make your predictions using the pKa values or using the Ka values. Higher pKa, higher pH of the acid in solution, lower acidity in solution
 

Related to Determining the Highest pH for Acid Solutions

1. What is the highest possible pH value?

The highest possible pH value is 14. This is considered a highly alkaline or basic solution.

2. How is the highest pH value determined?

The highest pH value is determined by measuring the concentration of hydroxide ions (OH-) in a solution. The more hydroxide ions present, the higher the pH will be.

3. What is the scale used to measure pH?

The pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 are considered acidic, while values above 7 are considered basic or alkaline.

4. What are some common substances with a high pH?

Some common substances with a high pH include bleach, ammonia, and baking soda. These substances are considered basic and have a pH above 7.

5. How does the highest pH value affect living organisms?

A high pH can be harmful to living organisms, as it can disrupt the balance of acids and bases in their bodies. This can lead to health issues and even death in extreme cases.

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