Volumetric Titration: Equipment and Cleaning

Volumetric Titration: Equipment and Cleaning

• A buret is a crucial piece of equipment in a volumetric titration, consisting of a graduation part, jet part, and tap.
• The graduation part is typically made of more silicate glass and is classified into three classes: Class A, Class B, and Class C, with Class A being the most accurate.
• Class B burets are commonly used in teaching institutions due to their acceptable accuracy and lower cost.
• The jet part allows for controlled and small flow of the solution into the titration flask.
• The tap is made of Teflon, a highly resistant polymer, and has an adjustable part to control the tap movement.

Cleaning the Buret

• Cleaning the buret is essential to prevent contamination and ensure accurate results.
• Use distilled water (DNS water) or deionized water to clean the buret, as tap water may contain impurities.
• Remove the buret from the clamp and hold it securely to prevent accidental spills.
• Close the tap before adding water to the buret to prevent leakage.
• Rotate the buret horizontally to clean the graduation part, then make it vertical to clean the jet part.
• Remove excess water from the graduation part and jet part after cleaning.

Rinsing the Buret with Titan

• After cleaning the buret with DNS water, rinse it with the titrand (sodium hydroxide solution in this case) to prevent dilution errors.
• Transfer some sodium hydroxide solution to a beaker, clean the beaker with DNS water, and then rinse it with the sodium hydroxide solution.
• Remove excess water from the beaker and rinse the inner walls with the sodium hydroxide solution.
• Transfer the sodium hydroxide solution to the buret, making sure to rinse the graduation part and jet part.

Importance of Proper Cleaning and Rinsing

• Failure to properly clean and rinse the buret can lead to errors in the titration due to contamination or dilution.
• Minimize the use of chemicals to avoid waste and environmental concerns.
• Always clean and rinse the buret, beaker, and other equipment to ensure accurate results in volumetric titration.Here are the study notes for the text:

Titration Techniques

• Importance of proper technique: prevents errors in experiment, ensures accurate results
• Key elements of correct titration technique:
  • Hold buret with left hand (for right-handed individuals) and titration flask with right hand
  • Keep buret at comfortable height, adjust to prevent leaking
  • Use white background to observe color change
  • Use left hand to operate buret, right hand to hold titration flask (for right-handed individuals)
  • Control tap with rounded motion, not direct operation

Preparing for Titration

• Use sticker papers to label beakers and flasks
• Clean and rinse glassware with deionized water
• Use a funnel to transfer titrant (e.g., sodium hydroxide) to buret
• Remove funnel after transferring titrant to prevent contamination
• Check buret for air bubbles, remove if necessary
• Ensure jet part of buret is free from air bubbles

Pipetting Techniques

• Use pipette bulb to suck solution
• Hold pipette vertically, press aspirate button to suck solution
• Release button to eject solution into beaker
• Clean pipette with deionized water, then rinse with small volume of titrant
• Use pipette to transfer 25 mL of hydrochloric acid to titration flask

Titration Flask Preparation

• Clean and rinse titration flask with deionized water
• Add acid-base indicator (e.g., phenolphthalein) to titration flask
• Add 2-3 drops of indicator to observe color change
• Use white background to observe color change

Performing Titration

• Hold buret and titration flask correctly (as above)
• Add titrant slowly, continuously, and carefully
• Swirl titration flask continuously to mix solutions
• Observe color change, stop adding titrant when endpoint is reached
• Use wash bottle to remove unreacted droplets from inner walls of titration flask
• Add small amounts of titrant drop by drop to avoid excess titrant

General Reminders

• Always remove funnel before starting titration
• Avoid mouth pipetting
• Don't touch pipette tip to benchtop or other surfaces to prevent contamination
• Take notes and record readings carefully

Volumetric Titration: Equipment and Cleaning

• A buret is a crucial piece of equipment in a volumetric titration, consisting of a graduation part, jet part, and tap.
• The graduation part is typically made of more silicate glass and is classified into three classes: Class A, Class B, and Class C, with Class A being the most accurate.
• Class B burets are commonly used in teaching institutions due to their acceptable accuracy and lower cost.
• The jet part allows for controlled and small flow of the solution into the titration flask.
• The tap is made of Teflon, a highly resistant polymer, and has an adjustable part to control the tap movement.

Cleaning the Buret

• Cleaning the buret is essential to prevent contamination and ensure accurate results.
• Use distilled water (DNS water) or deionized water to clean the buret, as tap water may contain impurities.
• Remove the buret from the clamp and hold it securely to prevent accidental spills.
• Close the tap before adding water to the buret to prevent leakage.
• Rotate the buret horizontally to clean the graduation part, then make it vertical to clean the jet part.
• Remove excess water from the graduation part and jet part after cleaning.

Rinsing the Buret with Titrand

• After cleaning the buret with DNS water, rinse it with the titrand (sodium hydroxide solution in this case) to prevent dilution errors.
• Transfer some sodium hydroxide solution to a beaker, clean the beaker with DNS water, and then rinse it with the sodium hydroxide solution.
• Remove excess water from the beaker and rinse the inner walls with the sodium hydroxide solution.
• Transfer the sodium hydroxide solution to the buret, making sure to rinse the graduation part and jet part.

Importance of Proper Cleaning and Rinsing

• Failure to properly clean and rinse the buret can lead to errors in the titration due to contamination or dilution.
• Minimize the use of chemicals to avoid waste and environmental concerns.
• Always clean and rinse the buret, beaker, and other equipment to ensure accurate results in volumetric titration.

Titration Techniques

• Proper technique is crucial in preventing errors in the experiment and ensuring accurate results.
• Key elements of correct titration technique include:
  • Holding the buret with the left hand and the titration flask with the right hand.
  • Keeping the buret at a comfortable height, adjusting to prevent leaking.
  • Using a white background to observe the color change.
  • Using the left hand to operate the buret and the right hand to hold the titration flask.
  • Controlling the tap with a rounded motion, not direct operation.

Preparing for Titration

• Use sticker papers to label beakers and flasks.
• Clean and rinse glassware with deionized water.
• Use a funnel to transfer the titrant (e.g., sodium hydroxide) to the buret.
• Remove the funnel after transferring the titrant to prevent contamination.
• Check the buret for air bubbles, remove if necessary.
• Ensure the jet part of the buret is free from air bubbles.

Pipetting Techniques

• Use a pipette bulb to suck the solution.
• Hold the pipette vertically, press the aspirate button to suck the solution.
• Release the button to eject the solution into the beaker.
• Clean the pipette with deionized water, then rinse with a small volume of the titrant.
• Use the pipette to transfer 25 mL of hydrochloric acid to the titration flask.

Titration Flask Preparation

• Clean and rinse the titration flask with deionized water.
• Add an acid-base indicator (e.g., phenolphthalein) to the titration flask.
• Add 2-3 drops of the indicator to observe the color change.
• Use a white background to observe the color change.

Performing Titration

• Hold the buret and titration flask correctly.
• Add the titrant slowly, continuously, and carefully.
• Swirl the titration flask continuously to mix the solutions.
• Observe the color change, stop adding the titrant when the endpoint is reached.
• Use a wash bottle to remove unreacted droplets from the inner walls of the titration flask.
• Add small amounts of the titrant drop by drop to avoid exceeding the endpoint.