To prepare a 0.1 M NaOH solution in a 50 mL volumetric flask, we need to determine how much solid sodium hydroxide (NaOH) is required.
Step 1: Determine Concentration and Volume
You want to prepare a 0.1 molar (M) solution of NaOH, and you need a final volume of 50 mL (or 0.050 L).
Step 2: Calculate Moles of NaOH Needed
The formula to calculate moles (n) is given by:
\[ n = C \times V \]
Where:
- \( C \) is the concentration in moles per liter (0.1 M).
- \( V \) is the volume in liters (50 mL = 0.050 L).
Now, substituting the values:
\[ n = 0.1 , \text{mol/L} \times 0.050 , \text{L} = 0.005 , \text{mol} \]
Step 3: Calculate Mass of NaOH Needed
Next, we need to find the mass of NaOH required to obtain 0.005 moles. We use the molar mass of NaOH for this. The molar mass of NaOH is approximately:
- Sodium (Na) = 22.99 g/mol
- Oxygen (O) = 16.00 g/mol
- Hydrogen (H) = 1.01 g/mol
Calculating the molar mass:
\[ \text{Molar mass of NaOH} = 22.99 + 16.00 + 1.01 = 40.00 , \text{g/mol} \]
Now, we can calculate the mass (m) needed using the formula:
\[ m = n \times \text{molar mass} \]
Substituting the values:
\[ m = 0.005 , \text{mol} \times 40.00 , \text{g/mol} = 0.200 , \text{g} \]
Summary of Prepared Solution
- Concentration Required: 0.1 M NaOH
- Volume of Solution Required: 50 mL
- Mass of NaOH Required: 0.200 g
Final Procedure
To prepare the 0.1 M NaOH solution:
- Weigh out 0.200 g of NaOH.
- Dissolve the NaOH in a portion of distilled water (less than 50 mL).
- Transfer the solution to a 50 mL volumetric flask.
- Fill the flask with distilled water up to the 50 mL mark, ensuring the solution is well mixed.
Safety Note: When working with NaOH, always use gloves and safety goggles, as it is a caustic substance.
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