Simple Titration – Acid/Base

Titration is a common laboratory technique used to determine the concentration of a substance in a solution. In this case, we will be performing a titration with sodium hydroxide (NaOH) and hydrochloric acid (HCl) to determine the concentration of HCl solution. Here is a detailed method for performing the titration, along with safety and environmental concerns:

Materials Required:

• Sodium hydroxide (NaOH) 0.1 M
• Hydrochloric acid (HCl) 0.1 M
• Distilled water
• Phenolphthalein indicator
• Burette
• Conical flask
• Pipette
• Beaker
• Safety goggles
• Lab coat
• Gloves

Safety Precautions:

• Wear safety goggles, lab coat, and gloves to protect your eyes, skin, and clothing from chemical spills or splashes.
• Handle NaOH and HCl with extreme caution as they are corrosive and can cause severe burns.
• Avoid inhaling the vapors produced during the titration, as they can irritate your respiratory system.
• Always use distilled water for diluting the solutions to avoid any impurities in the water.
• Keep a neutralizing solution of 1% sodium bicarbonate on hand in case of accidental spills or splashes.
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Environmental Concerns:

• Dispose of all chemical wastes according to local regulations and guidelines.
• Rinse all glassware thoroughly with water before disposal.
• Never pour any chemicals down the drain or in the trash.

Procedure:

1. Using a pipette, measure out a volume of the HCl solution (typically 25.0 mL) and transfer it to a clean conical flask.

2. Add a few drops of phenolphthalein indicator to the HCl solution in the flask. The indicator will turn pink in the presence of excess NaOH.

3. Fill the burette with the NaOH solution and note down the initial burette reading.

4. Slowly add the NaOH solution from the burette into the HCl solution in the conical flask, swirling the flask gently after each addition.

5. Continue adding NaOH solution until the pink colour of the indicator just disappears. This is known as the endpoint of the titration.

6. Record the final burette reading.

7. Repeat the titration two more times to obtain an average volume of NaOH required to neutralize the HCl.

Calculations:

Using the average volume of NaOH solution required to neutralize the HCl, we can calculate the concentration of HCl in the solution using the formula:

Molarity of HCl = Molarity of NaOH x Volume of NaOH used / Volume of HCl used

Safety and environmental concerns are critical when performing a titration. Follow these guidelines carefully to ensure your safety and the environment’s protection.