Answer to Question #265615 in General Chemistry for Rainie

Question

Diagram 1 shows the preparation of standard solution of potassium hydroxide, KOH by dissolving 5.6 g of potassium hydroxide in distilled water and making the volume up to 100 cm³.

What is the volume of the standard solution prepared above that should be used if a student wants to prepare 50 cm³ of 0.5 mol dm^-3 potassium hydroxide solution?

Answer 1

50 cm³ = 0.05 dm³

Conc = 0.5 Mol dm^-3

Amount of KOH in mol = concentration in mol dm^-3 × volume in dm³

= 0.5 mol dm^-3 × 0.05 dm³

= 0.025 mol

Mass of KOH = 0.025×56.1056 = 1.40g

Which is equal to 1.4 cm³

So volume is 1.4 cm³