Simple Dilutions and Solutions

Why is standardisation of the prepared HCl solution using disodium tetraborate necessary?

To accurately determine the true concentration of the acid for reliable titration results.

How does the Pearson Square method help in preparing diluted acid solutions?

It calculates the proportions of stock and solvent needed to reach a desired concentration.

Why is phenolphthalein used in titrations involving NaOH?

It acts as an indicator, turning pink at the endpoint of base titrations.

How do you calculate the volume of 37% HCl (density 1.19 g/mL) to make 250 mL of 0.1N solution?

Use: Volume = (0.1 × 36.46 × 250) / (1000 × 1.19 × 0.37) ≈ 2.1 This formula converts normality to volume by accounting for HCl's molar mass, density, and concentration. This allows for accurate preparation of the desired solution.

What is a challenge in weighing concentrated HCl or NaOH pellets?

HCl is a volatile liquid; NaOH is hygroscopic and absorbs moisture from the air.