Hi, I'm a little stuck on this problem:
Find the pH of the Hydrochloric acid solution when 5.0 mL of concentrated HCl, with a specific gravity of 1.18 and has 37% (w/w) purity is diluted to 2.0L
2L of what?
I assume you mean 2.0 L of solution with water.
What's the molarity of the 37% (first stuff)? That's
1.18g/mL x 1000 mL x 0.37% = g HCl
gHCl/molar mass HCl = moles HCl/L = M
Then use
c1v1 = c2v2
c1 = M from above
v1 = 5.0 mL
c2 = solve for this
v2 = 2000 mL.
To find the pH of the hydrochloric acid solution, we need to calculate the concentration of HCl in the diluted solution first. Here's how you can solve the problem:
Step 1: Calculate the amount of HCl in the concentrated solution:
- The specific gravity of the concentrated HCl is given as 1.18. Specific gravity is the ratio of the density of a substance to the density of a reference substance (usually water). Since the reference substance (water) has a specific gravity of 1.00, we can assume that the specific gravity of the concentrated HCl is equal to its density in g/mL. So, the density of the concentrated HCl is 1.18 g/mL.
- The volume of the concentrated HCl is given as 5.0 mL.
- To calculate the mass of HCl, we multiply the volume by the density: mass = volume × density = 5.0 mL × 1.18 g/mL.
Step 2: Calculate the amount of HCl in the diluted solution:
- The concentration of HCl in the concentrated solution is given as 37% (w/w) purity. This means that 37% of the concentrated HCl is pure HCl by weight.
- To calculate the amount of HCl in grams, we multiply the mass of the concentrated solution by the purity percentage: amount of HCl = mass of concentrated solution × purity % = (5.0 mL × 1.18 g/mL) × (37/100).
Step 3: Calculate the concentration of HCl in the diluted solution:
- The diluted solution has a final volume of 2.0 L.
- To calculate the concentration of HCl in moles per liter (M), we divide the amount of HCl in grams by the molar mass of HCl, and then divide by the final volume in liters: concentration = (amount of HCl in grams / molar mass of HCl) / final volume in liters.
Step 4: Calculate the pOH of the solution:
- The pOH is calculated using the formula: pOH = -log10(concentration).
Step 5: Calculate the pH of the solution:
- The pH of the solution can be obtained by subtracting the pOH from 14 (as pH + pOH = 14).
By following these steps, you should be able to find the pH of the hydrochloric acid solution after it is diluted to 2.0L.