Solve 5pH Solution from Citric Acid (1L)

In summary, the conversation discusses how to make a 5pH solution from citric acid and whether it is possible to do so accurately using paper calculations. The conversation also raises the possibility of using a citric buffer instead.
  • #1
vande060
186
0

Homework Statement



how would you make a 5pH solution from citric acid(1L)



Homework Equations



pH= log(H+)


The Attempt at a Solution



So I will try to work backwards from the [H+]

antilog(-5) = 10^-5 M H+ needed

this number can be divided by 3, because citric acid is triprotic

3.33*10^-6 moles * 210.14 g/mol = 7*10^-4 g brought to volume with 1 liter
 
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  • #2
That would be way too simple. Citric acid is a weak one, with pKa values of 3.13, 4.76 and 6.40, so at pH 5.0 none of the protons is dissociated 100%. That means your assumption is faulty, and concentration you calculated - while not far from the correct answer - is too low.

To be honest, I can't think of a simple and accurate approach to solving the question on paper. It is not a problem using - although it requires some trial and error to get the correct concentration, as program calculates pH for a given concentration, but it doesn't work the other way around.

Are you sure the problem is about using citric acid and not about preparing citric buffer?
 

FAQ: Solve 5pH Solution from Citric Acid (1L)

What is the purpose of making a 5pH solution from citric acid?

The purpose of making a 5pH solution from citric acid is to have a specific and consistent pH level for use in various experiments or applications. The 5pH level is commonly used in the food and beverage industry as a preservative and in cleaning products as a disinfectant.

How do I make a 5pH solution from citric acid?

To make a 5pH solution from citric acid, you will need to mix 1L of water with a specific amount of citric acid. The exact amount of citric acid needed will vary depending on its concentration and the desired pH level. It is recommended to use a pH meter or indicator strips to accurately measure the pH level of the solution as you mix it.

What are the safety precautions when working with citric acid?

Citric acid is a corrosive substance and should be handled with caution. It is important to wear protective gear such as gloves, goggles, and a lab coat when handling citric acid. It is also recommended to work in a well-ventilated area and to avoid inhaling the fumes. In case of accidental contact with the skin or eyes, immediately rinse with water.

Can I adjust the pH level of the solution if it is not exactly 5pH?

Yes, the pH level of the solution can be adjusted by adding more citric acid to decrease the pH level or adding more water to increase the pH level. It is important to mix the solution thoroughly and check the pH level again after each adjustment to ensure accuracy.

How should I store the 5pH solution from citric acid?

The 5pH solution from citric acid should be stored in a tightly sealed container in a cool and dry place. It is best to use the solution within a few days of making it, as it may lose its potency over time. Label the container clearly with the date and pH level for future reference.

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