Hello. I need to prepare 1 liter of a buffer of 0.1M , pH=6.0. (Acid =HCl, base=Sodium tetraborate)
I have in the lab: 320331 Sigma-Aldrich hydrochloric acid ACS reagent, 37% .
and 221732 Sigma-Aldrich Sodium Tetraborate (Molecular Weight : 201.22 g/mol).
So what quantity of Sodium tetraborate I need to put in the Di-water?
And first I put the sodium tetraborate, and then the necessary quantity of HCl to obtain the desired pH ?
To prepare 1 liter of a buffer with a concentration of 0.1 M and a pH of 6.0 using hydrochloric acid (HCl) as the acid and sodium tetraborate as the base, you will need to follow a specific procedure. Here are the steps:
Step 1: Calculate the amount of sodium tetraborate needed:
- Determine the number of moles of sodium tetraborate required using the formula:
moles = concentration (M) x volume (L)
- Substituting the given values, we have:
moles = 0.1 M x 1 L = 0.1 moles
Step 2: Convert moles to grams:
- Multiply the number of moles calculated in step 1 by the molar mass of sodium tetraborate (Na2B4O7):
grams = moles x molar mass
- Substituting the values, we get:
grams = 0.1 moles x 201.22 g/mol = 20.122 grams
Therefore, you will need to add 20.122 grams of sodium tetraborate to the distilled water.
Step 3: Dissolve sodium tetraborate in distilled water:
- Take a suitable container, measure 1 liter of distilled water, and add it to the container.
- Gradually add the calculated amount of sodium tetraborate (20.122 grams) to the water.
- Stir the solution gently until the sodium tetraborate has completely dissolved.
Step 4: Adjust pH with hydrochloric acid:
- Measure the pH of the solution using a pH meter or pH indicator strips. If it is not at the desired pH of 6.0, proceed to the next step.
- Slowly and incrementally add hydrochloric acid (HCl) to the solution, while measuring the pH after each addition.
- Continue adding the HCl until the desired pH of 6.0 is reached. Make sure to stir the solution after each addition and leave sufficient time for the pH to stabilize before taking a reading.
Remember to handle chemicals with care and follow proper safety protocols when working in the laboratory.