Did I Prepare My Phosphate Buffer Solution Correctly?

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In summary, a phosphate buffer is a type of buffer solution used in scientific experiments to maintain a stable pH. It consists of a mixture of sodium phosphate salts and helps to neutralize any added acids or bases through a process called buffering. Phosphate buffers are important in research because they prevent negative effects on pH-dependent reactions and processes. The optimal pH range for a phosphate buffer is 6.8 to 7.2 and it is prepared by mixing specific ratios of sodium phosphate salts and adjusting the pH using an acid or base.
  • #1
brendw2005
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Hi everybody!
I want to prepare 1000 ml of 0.1M phosphate buffer solution, pH = 7.0. I used Henderson Hasselbach's equation: pH = pka + log [salt]/[acid]. I obtained 0.062 moles of H2PO4- and 0.038 moles of HPO42-. Where I am wrong? Thanks a lot!
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  • #2
Show your work. Which pKa did you use? What species did you use for [salt] and [acid]?
 
  • #3
Thanks for replying!

I used (H2PO4)- ↔H+ + (HPO4)2-
Ka for this equation is 6.2*10-8, deci pKa = 7.21.
Salt = (HPO4)2-
Acid = (H2PO4)-
 
  • #4
I get the same...
 
  • #5
So, I did it right! Thanks!
 

What is a phosphate buffer?

A phosphate buffer is a type of buffer solution that is commonly used in scientific experiments to maintain a stable pH. It is made up of a mixture of sodium phosphate salts and can resist changes in pH when acids or bases are added.

Why is a phosphate buffer important in scientific research?

A phosphate buffer is important because it helps to maintain a stable pH in experiments. This is important because many chemical reactions and biological processes are pH-dependent and can be negatively affected by changes in pH.

How does a phosphate buffer work?

A phosphate buffer works by neutralizing any added acids or bases through a process called buffering. This is achieved through the equilibrium between the weak acid and its conjugate base in the buffer solution. The two components work together to maintain a stable pH.

What is the optimal pH range for a phosphate buffer?

The optimal pH range for a phosphate buffer is between 6.8 and 7.2. This range is close to the physiological pH of many biological systems, making phosphate buffers suitable for a variety of experiments in biology and biochemistry.

How is a phosphate buffer prepared?

A phosphate buffer can be prepared by mixing a specific ratio of monobasic and dibasic sodium phosphate salts with water. The exact ratio depends on the desired pH and can be calculated using the Henderson-Hasselbalch equation. The solution is then adjusted to the final desired pH using either an acid or a base.

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