Paper 2 - LO3

What is the purpose of titration?

To determine the concentration of an acid or base.

What equipment is commonly used for measuring small volumes of solutions accurately?

A graduated pipette.

What is the significance of the pH range of an indicator?

It should match the rapid change in pH at the endpoint of the titration.

What is the balanced equation for the reaction between sulfuric acid and sodium hydroxide?

H2SO4 + 2NaOH → Na2SO4 + 2H2O.

How do you calculate the concentration of an unknown acid using titration?

Use the formula c = n/V, where c is concentration, n is moles, and V is volume.

What is the mole ratio of NaOH to H2SO4 in the neutralization reaction?

2:1.

How do you convert cm³ to dm³?

Divide by 1000.

What is the concentration of H2SO4 if 20.0 cm³ of 1.0 mol/dm³ NaOH neutralizes 25.5 cm³ of H2SO4?

0.392 mol/dm³.

What are the advantages of using an auto-titrator?

Reduces labor time, avoids transcription errors, and improves accuracy.

What is the endpoint in a titration?

The point at which the indicator changes color.

What color does methyl orange turn in acidic and alkaline solutions?

Orange in acid and yellow in alkali.

What color does phenolphthalein turn in acidic and alkaline solutions?

Colorless in acid and pink in alkali.

What color does bromothymol blue turn in acidic and alkaline solutions?

Yellow in acid and green in alkali.

What is the mass of NaOH required to prepare a 0.1 mol/dm³ solution?

4 g of NaOH per 1000 cm³ of distilled water.

What is the molar mass of NaOH?

40 g/mol.

How do you calculate the amount of solute in moles?

Use the formula: amount = concentration × volume.

What is the concentration of hydrochloric acid if 25.0 cm³ of 0.100 mol/dm³ NaOH neutralizes 20.00 cm³ of HCl?

0.125 mol/dm³.

How do you calculate the concentration of HCl in g/dm³?

Multiply the concentration in mol/dm³ by the molar mass of HCl (36.5 g/mol).

What is the concentration of HCl if the mass is 4.56 g in 1 dm³?

0.125 mol/dm³.

What is the significance of concordant readings in titration?

They indicate reliable and consistent results.

What is the volume range for a graduated pipette?

From 5 ml to 50 ml.