GCSE Chemistry Revision "Required Practical 2: Carrying out a Titration" (Triple)

Summary

This video explains the procedure for carrying out a titration, a key experiment in chemistry. It covers the steps of transferring alkali into a conical flask, adding an indicator, and performing the titration by gradually adding acid until neutralization occurs. The video emphasizes accurate measurement, particularly in reading the burette, and the importance of repeating the titration to ensure reliable results. By the end, viewers will be able to describe the titration process and understand its role in determining the concentration of an acid.

Takeaways

• 😀 Titrations are a procedure used to determine the concentration of an acid by neutralizing it with a known volume and concentration of an alkali.
• 😀 The reaction in the titration is a neutralization reaction, such as sulfuric acid reacting with sodium hydroxide.
• 😀 A pipette is used to transfer a known volume of sodium hydroxide into a conical flask, ensuring accurate volume measurement.
• 😀 Methyl orange is commonly used as an indicator, turning from yellow to red when the acid neutralizes the alkali.
• 😀 The conical flask reduces the risk of splashing during the titration process.
• 😀 When using a pipette, it is essential to allow the liquid to drain naturally rather than blowing it out, which would cause inaccuracies.
• 😀 The sulfuric acid is added drop by drop from a burette to the alkali solution until the color change (yellow to red) indicates neutralization.
• 😀 It’s important to swirl the solution to ensure proper mixing of the acid and alkali.
• 😀 To accurately read the burette, align your eye level with the surface of the liquid and read at the bottom of the meniscus.
• 😀 A titration should be repeated several times until two readings are within 0.1 cm³ of each other, and then a mean volume is calculated.
• 😀 Once the volume of acid required to neutralize the alkali is determined, this can be used to calculate the concentration of the acid in a subsequent calculation.

Q & A

What is the purpose of a titration in this video?

The purpose of a titration in this video is to determine the concentration of an unknown acid by neutralizing it with a base (sodium hydroxide) of known concentration.

What chemical reaction is involved in the titration described?

The chemical reaction involved in the titration is a neutralization reaction between sulfuric acid (H₂SO₄) and sodium hydroxide (NaOH).

Why is a conical flask used in the titration procedure?

A conical flask is used because its shape reduces the risk of splashing, making it safer during the titration process.

How is the pipette used correctly in this experiment?

The pipette is used by drawing liquid into it with a pipette filler, but it is important to allow the liquid to drain naturally rather than blowing it out to ensure the correct volume is transferred.

What is the role of the indicator in this titration process?

The indicator, such as methyl orange, is added to the alkali solution to help observe the color change when the neutralization reaction is complete. Methyl orange changes color from yellow to red when the solution is neutralized.

Why is a white tile used during the titration?

A white tile is placed under the conical flask to make it easier to see the color change in the solution, improving the accuracy of detecting the endpoint of the titration.

How should the acid be added to the alkali during the titration?

The acid should be added drop by drop once the color change begins to appear, while continuously swirling the solution to ensure thorough mixing of the acid and alkali.

What is the importance of reading the burette correctly?

It is important to read the burette at the bottom of the meniscus to ensure an accurate measurement of the volume of acid used. The meniscus curves, and reading at the bottom ensures precise results.

How many titrations should be performed to ensure reliable results?

The titration should be repeated several times until two readings are within 0.1 cm³ of each other. This ensures accuracy and consistency in the results.

What do you do after performing the titration and obtaining the required volume of acid?

Once the volume of acid required for neutralization is determined, you can use this information, along with the known concentration of the alkali, to calculate the concentration of the acid.