Neutralimetry

Flashcards based on practical exam questions about neutralimetry, covering topics from buret usage to titration techniques.

Why rinse the buret with the titrant before use?

To prevent dilution/contamination of the titrant for accurate measurement.

How should you read the volume on a buret?

Read the bottom of the meniscus at eye level to avoid parallax error.

What indicator is commonly used in acid-base titration?

Phenolphthalein.

What indicates the endpoint when using phenolphthalein?

A faint pink color that lasts at least 15 seconds.

Why use NaOH immediately after preparation?

It absorbs CO₂ from the air, altering its concentration.

What if the titration surpasses the endpoint?

Perform a back-titration.

Why add acid to water and not the reverse?

To prevent violent splashing and exothermic reactions.

Why is phenolphthalein preferred?

It has a clear and sharp color change near the neutral point.

What is the purpose of standardizing NaOH using KHP?

To determine the exact molarity of the NaOH solution.

Why is KHP a suitable primary standard?

It is pure, stable, non-hygroscopic, and has a high molecular weight.

What does a persistent pink endpoint suggest?

Neutralization has occurred, and the solution is slightly basic.

What safety precautions for handling NaOH?

Wear gloves and goggles; NaOH is corrosive and can cause burns.

Why swirl the flask during titration?

To mix reactants thoroughly and evenly detect the endpoint.

Why use distilled water in preparations?

Distilled water is free from ions and contaminants.

What error if air bubbles are in the buret tip?

Inaccurate volume readings, leading to erroneous results.

Why label prepared solutions properly?

To identify contents, avoid confusion, and ensure correct usage.

What's the function of a buret stand and clamp?

To securely hold the buret vertically for accurate dispensing.

Why avoid excess stopcock grease?

It can enter the bore, affecting flow and accuracy.

What is “rinsing by portions”?

Rinsing the buret multiple times with small volumes of the titrant.

What happens if the buret is not clean before use?

Liquid may adhere to the walls, leading to inaccurate readings.

Why is back-titration necessary in vinegar analysis?

To correct over-titration and accurately reach the endpoint.

How can atmospheric CO₂ interfere with titration?

It can react with NaOH, forming carbonates and affecting molarity.

Best way to mix a solution during flask titration?

Swirl the flask gently but continuously.

When is the buret reading taken?

At the beginning (initial) and end (final) of the titration.

Why must the pink endpoint persist for 15 seconds?

To ensure complete neutralization and that the reaction is finished.