Hi, Can anyone suggest a protocol for preparing 1 Litre ammonical solution (pH 7.8, NH4-N, 3000 mg/L) from NH4Cl and NaOH? I have worked out that I need 10.7g NH4CL and 0.45 g NaOH -is this correct? I am assuming that 1st step is to prepare 0.45 g NaoH in 0.5 L distilled water and then to that add 10.7 g NH4CL solution in 0.5 L of distilled water.Total volume is 1 L? Or is there another way
To prepare a 1-Litre ammonical solution (pH 7.8, NH4-N, 3000 mg/L) from NH4Cl and NaOH, here is a step-by-step procedure:
1. Calculate the required amounts of NH4Cl and NaOH:
- Firstly, convert the NH4-N concentration given in mg/L to grams per litre.
NH4-N concentration (mg/L) * 1 g/1000 mg = NH4-N concentration (g/L)
- The required amount of NH4Cl can be calculated using the formula:
NH4-N concentration (g/L) * NH4Cl molar mass (g/mol) = NH4Cl amount (g)
- Similarly, calculate the amount of NaOH required using the same method.
2. Prepare the NaOH solution:
- In a suitable container, dissolve 0.45 grams of NaOH in around 500 mL of distilled water.
- Stir until the NaOH is completely dissolved.
- Ensure the volume does not exceed 500 mL at this stage.
3. Prepare the NH4Cl solution:
- In another container, dissolve 10.7 grams of NH4Cl in around 500 mL of distilled water.
- Stir until the NH4Cl is completely dissolved.
- Again, ensure the volume does not exceed 500 mL at this stage.
4. Combine the solutions:
- Slowly pour the NH4Cl solution into the NaOH solution while stirring continuously.
- Continue stirring until the two solutions are thoroughly mixed.
- After mixing, the total volume should be around 1 litre.
5. Check the pH:
- Measure the pH of the solution using a suitable pH meter.
- Adjust the pH to 7.8 using additional NaOH or HCl if necessary.
- Be cautious and carefully adjust the pH in small increments while monitoring it closely.
6. Once the desired pH is achieved, dilute the solution to the final volume of 1 litre:
- Add additional distilled water to bring the total volume up to 1 litre.
- Stir gently to ensure complete mixing.
Remember to follow proper laboratory safety guidelines, wear appropriate protective equipment, and handle chemicals with caution.
To prepare 1 liter of ammonical solution with a pH of 7.8, NH4-N concentration of 3000 mg/L, using NH4Cl and NaOH, you need to follow these steps:
1. Calculate the amount of NH4Cl and NaOH required:
- Determine the molar mass of NH4Cl (53.5 g/mol) and NaOH (40.0 g/mol).
- Convert the concentration of NH4-N (3000 mg/L) to moles per liter by dividing by the molar mass of NH4 (14 g/mol).
- The moles of NH4 in 1 liter would then be 3000 mg / 1000 g * (1 mol / 14 g) = 214.29 mmol/L.
- For every NH4 molecule, you need one molecule of NaOH to neutralize it, so you also need 214.29 mmol/L of NaOH.
2. Prepare NaOH solution:
- Weigh 0.45 g of NaOH using a balance.
- Dissolve the measured NaOH in approximately 500 mL of distilled water.
- Stir the solution to ensure complete dissolution of NaOH.
- If needed, adjust the volume with distilled water to make it exactly 500 mL.
3. Prepare NH4Cl solution:
- Weigh 10.7 g of NH4Cl using a balance.
- Dissolve the measured NH4Cl in approximately 500 mL of distilled water.
- Stir the solution until NH4Cl is completely dissolved.
- If needed, adjust the volume with distilled water to make it exactly 500 mL.
4. Combine the solutions:
- Pour the NH4Cl solution into a suitable container.
- Slowly add the NaOH solution to the container while stirring.
- Continue stirring until the solutions are thoroughly mixed.
5. Adjust the volume:
- Transfer the combined solution to a 1-liter volumetric flask.
- Adjust the volume with distilled water to reach the 1-liter mark on the flask.
- Make sure the solution is thoroughly mixed.
Once you have followed these steps, you should have a 1-liter ammonical solution with a pH of 7.8 and an NH4-N concentration of 3000 mg/L.