Acid Base Titration | Chemistry for Grade 11 (IGCSE) PDF Download

Acid-Base Titrations

• Titrations are a method of analyzing solution concentrations
• They help determine the exact amount of alkali needed to neutralize a given quantity of acid, and vice versa
• These experiments may involve calculating the moles in a specified quantity, as well as the concentration or volume required to neutralize an acid or base
• Titrations are also useful for the preparation of salts

Materials Required for Titration

• 25 cm³ volumetric pipette
• Pipette filler
• 50 cm³ burette
• 250 cm³ conical flask
• Small funnel
• 0.1 mol/dm³ sodium hydroxide solution
• Sulfuric acid – concentration unknown
• A suitable indicator
• Clamp stand, clamp & white tile

Steps in Performing a Titration

Describing the method:

• Use the pipette and pipette filler to transfer exactly 25 cm³ of sodium hydroxide solution into the conical flask.
• Position the conical flask on a white tile with the burette tip inside.
• Add a few drops of a suitable indicator to the solution in the conical flask.
• Conduct a rough titration by incrementally adding the solution from the burette in 1 – 3 cm³ portions while swirling the flask vigorously.
• Close the tap swiftly when the sharp color change signals the end-point and record the volume, aligning your eye with the meniscus.
• Repeat the titration process with a fresh batch of sodium hydroxide.
• Approach the rough end-point volume carefully, adding solution drop by drop until the indicator changes color precisely.
• Record the volume accurately to the nearest 0.05 cm³.
• Repeat the titration until two concordant results are achieved (results within 0.1 cm³ of each other) to enhance precision.

Indicators

• Indicators play a crucial role in titration by indicating the endpoint.
• Wide range indicators like litmus are unsuitable due to their lack of a sharp color change at the endpoint.
• On the other hand, indicators like methyl orange and phenolphthalein are highly suitable for this purpose.
• Here are some common indicators along with their respective colors: