Question
Prepare 0.1 molar HCl in 100ml of volumetric flask from stock solution of 37%. ( density = 1.19g/cm3. Find the volume of HCl and Show all necessary steps
Answers
Answered by
GPT-4o mini
To prepare a 0.1 M solution of hydrochloric acid (HCl) from a concentrated 37% solution, we will need to carry out a few calculations. Here are the steps to follow:
### Step 1: Find the Molarity of the Stock Solution
1. **Determine the density of the stock solution**: Given as 1.19 g/cm³.
2. **Concentration of HCl in 37% solution**: This means 37 g of HCl are present in 100 g of the solution.
3. **Calculate the mass of the solution in 1 liter (1000 g)**:
\[
\text{Mass of solution} = \frac{1000 \, \text{g solution}}{100 \, \text{g}} = 1000 \times 0.37 \, \text{g HCl} = 370 \, \text{g HCl} \text{ in 1000 g of solution}
\]
4. **Find the number of moles of HCl in 370 g**:
- Molar mass of HCl ≈ 36.46 g/mol
\[
\text{Moles of HCl} = \frac{370 \, \text{g}}{36.46 \, \text{g/mol}} \approx 10.14 \, \text{mol}
\]
5. **Calculate the molarity of the stock solution**:
\[
\text{Molarity (M)} = \frac{\text{Moles}}{\text{Volume in L}} = \frac{10.14 \, \text{mol}}{1 \, \text{L}} \approx 10.14 \, \text{M}
\]
### Step 2: Calculate the Volume of Stock Solution Needed
Now that we have the molarity of the stock solution, we can calculate how much we need to dilute to get 0.1 M in a 100 mL solution.
1. **Use dilutions formula**: \( C_1V_1 = C_2V_2 \)
- Where:
- \( C_1 \) = concentration of stock solution (10.14 M)
- \( V_1 \) = volume of stock solution needed (in L)
- \( C_2 \) = concentration of the diluted solution (0.1 M)
- \( V_2 \) = final volume of diluted solution (0.1 L)
Plug in the known values:
\[
(10.14 \, \text{M}) \times V_1 = (0.1 \, \text{M}) \times (0.1 \, \text{L})
\]
\[
10.14 \, V_1 = 0.01
\]
\[
V_1 = \frac{0.01}{10.14} \approx 0.000985 \, \text{L} \approx 0.985 \, \text{mL}
\]
### Step 3: Prepare the Solution
To prepare the desired concentration of HCl:
1. **Measure approximately 0.985 mL of the concentrated HCl solution** using a pipette.
2. **Dilute with distilled water** in a 100 mL volumetric flask. Add distilled water until the total volume reaches the 100 mL mark.
### Step 4: Safety Measures
- Always wear appropriate personal protective equipment (PPE) such as gloves, goggles, and a lab coat when handling concentrated acids.
- Perform all dilutions in a fume hood or well-ventilated area to avoid inhalation of fumes.
### Summary
To prepare a 0.1 M HCl solution in 100 mL, you need to take approximately **0.985 mL of 37% HCl** and dilute it with distilled water to a final volume of **100 mL**.
### Step 1: Find the Molarity of the Stock Solution
1. **Determine the density of the stock solution**: Given as 1.19 g/cm³.
2. **Concentration of HCl in 37% solution**: This means 37 g of HCl are present in 100 g of the solution.
3. **Calculate the mass of the solution in 1 liter (1000 g)**:
\[
\text{Mass of solution} = \frac{1000 \, \text{g solution}}{100 \, \text{g}} = 1000 \times 0.37 \, \text{g HCl} = 370 \, \text{g HCl} \text{ in 1000 g of solution}
\]
4. **Find the number of moles of HCl in 370 g**:
- Molar mass of HCl ≈ 36.46 g/mol
\[
\text{Moles of HCl} = \frac{370 \, \text{g}}{36.46 \, \text{g/mol}} \approx 10.14 \, \text{mol}
\]
5. **Calculate the molarity of the stock solution**:
\[
\text{Molarity (M)} = \frac{\text{Moles}}{\text{Volume in L}} = \frac{10.14 \, \text{mol}}{1 \, \text{L}} \approx 10.14 \, \text{M}
\]
### Step 2: Calculate the Volume of Stock Solution Needed
Now that we have the molarity of the stock solution, we can calculate how much we need to dilute to get 0.1 M in a 100 mL solution.
1. **Use dilutions formula**: \( C_1V_1 = C_2V_2 \)
- Where:
- \( C_1 \) = concentration of stock solution (10.14 M)
- \( V_1 \) = volume of stock solution needed (in L)
- \( C_2 \) = concentration of the diluted solution (0.1 M)
- \( V_2 \) = final volume of diluted solution (0.1 L)
Plug in the known values:
\[
(10.14 \, \text{M}) \times V_1 = (0.1 \, \text{M}) \times (0.1 \, \text{L})
\]
\[
10.14 \, V_1 = 0.01
\]
\[
V_1 = \frac{0.01}{10.14} \approx 0.000985 \, \text{L} \approx 0.985 \, \text{mL}
\]
### Step 3: Prepare the Solution
To prepare the desired concentration of HCl:
1. **Measure approximately 0.985 mL of the concentrated HCl solution** using a pipette.
2. **Dilute with distilled water** in a 100 mL volumetric flask. Add distilled water until the total volume reaches the 100 mL mark.
### Step 4: Safety Measures
- Always wear appropriate personal protective equipment (PPE) such as gloves, goggles, and a lab coat when handling concentrated acids.
- Perform all dilutions in a fume hood or well-ventilated area to avoid inhalation of fumes.
### Summary
To prepare a 0.1 M HCl solution in 100 mL, you need to take approximately **0.985 mL of 37% HCl** and dilute it with distilled water to a final volume of **100 mL**.