To prepare 100 mL of a 6.0 M hydrochloric acid (HCl) solution, you need to understand the relationship between molarity, volume, and the amount of solute required. Molarity (M) is a way to express concentration, indicating the number of moles of solute per liter of solution.
Here’s a step-by-step guide to help you prepare this solution:
- Calculate the number of moles needed:
First, you need to determine how many moles of HCl you require. Molarity (M) = moles of solute / volume of solution (L). Since you want 100 mL (or 0.1 L) of a 6.0 M solution:
Number of moles = Molarity × Volume = 6.0 moles/L × 0.1 L = 0.6 moles
- Determine the mass of HCl required:
Next, find the mass of HCl corresponding to 0.6 moles. The molecular weight of HCl is approximately 36.46 g/mol.
Mass = moles × molecular weight = 0.6 moles × 36.46 g/mol = 21.876 g
- Measure the concentrated HCl:
Concentrated hydrochloric acid usually has a molarity of about 12 M. To find out how much concentrated HCl you need to achieve 0.6 moles, use the formula:
Volume (L) = moles / Molarity = 0.6 moles / 12 M = 0.05 L or 50 mL
- Prepare the solution:
Take 50 mL of concentrated HCl and carefully dilute it with distilled water to a total volume of 100 mL. Always add acid to water, not the other way around, to ensure safety and prevent dangerous splashing.
- Final check:
After diluting, ensure that the final volume is 100 mL. You now have a 6.0 M HCl solution ready to use.
Always handle HCl with care, wearing appropriate protective equipment, such as gloves and goggles, as it is corrosive and can cause severe burns.