Describe, in detail, how to make 5.5 liters of a 2.5 molar HCl solution from a 10.5 molar HCl stock solution.
mLsoln1 x Msoln1 = mLsoln2 x Msoln2.
The USUAL way is to measure the amount of HCl calculated above to a 5.5 L volumetric flask, then make to the mark with distilled water. However, as far as I know, 5.5 L volumetric flasks don't exist so it may take some ingenuity. I would solve this problem by adding the calculated amount of HCl to a 500 mL (0.500L) volumetric flask and making to the mark with distilled water. Shake thoroughly and quantitatively transfer the contents of the 500 mL flask to a 5.00 L volumetric flask, then make to the mark in the 5.00 L flask with distilled water.
To make 5.5 liters of a 2.5 molar HCl solution from a 10.5 molar HCl stock solution, you will need to use the concept of dilution. Dilution involves adding a solvent (in this case, water) to the concentrated solution (stock solution) to decrease its molarity to the desired concentration.
Here's a step-by-step guide on how to make the desired solution:
1. Start by calculating the amount of HCl you need to reach the desired concentration. To do this, use the formula:
moles of solute = Molarity × Volume (in liters)
The moles of solute you need is calculated as:
moles of solute = Molarity × Volume (in liters)
= 2.5 mol/L × 5.5 L
= 13.75 moles
2. Now, calculate the volume of the stock solution needed to obtain the desired moles of solute. To do this, rearrange the formula from step 1:
Volume of stock solution = moles of solute / Molarity of stock solution
Plugging in the values:
Volume of stock solution = 13.75 moles / 10.5 mol/L
= 1.31 liters (rounded to two decimal places)
Therefore, you need 1.31 liters of the 10.5 molar HCl stock solution.
3. Next, measure out the required volume of the stock solution (1.31 liters) using a measuring cylinder or another suitable container.
4. Transfer the measured stock solution to a larger container, such as a volumetric flask or a beaker.
5. Add water to the container while stirring to make up the total desired volume of 5.5 liters. The water added will be:
Volume of water = Total volume - Volume of stock solution
= 5.5 L - 1.31 L
= 4.19 liters
Therefore, add 4.19 liters of water to the container while stirring the solution.
6. Finally, thoroughly mix the solution, ensuring that the HCl is evenly distributed throughout the mixture.
By following these steps, you will successfully prepare 5.5 liters of a 2.5 molar HCl solution from a 10.5 molar HCl stock solution. Remember to take appropriate safety precautions when handling strong acids like HCl.