Chemistry - 4 Chemical Calculations - Required Practical 2: Neutralisation

Aims:

  • determine the reacting volumes of solutions of a strong acid and a strong alkali by titration

Risk Assessment:

  • chemicals can damage eyes

  • glass implements are delicate

Safety:

  • wear goggles

  • be cautious with glass implements and, of broken, do not touch remains and dispose carefully and properly

Equipment:

  • 25 cm³ volumetric pipette

  • pipette filler

  • 50 cm³ burette

  • 250 cm³ conical flask

  • small funnel

  • clamp stand and clamp

  • white tile

  • 0.1 mol/dm³ sodium hydroxide solution (concentration shown)

  • 0.08 mol/dm³ sulfuric acid (concentration not shown)

  • phenolphthalein indicator

Control variables:

n/a

Independent variable:

n/a

Dependent variable:

n/a

Method:

  1. Transfer 25 cm³ sodium hydroxide solution into a conical flask using a pipette and pipette filler

  2. Add 2-5 drops of phenolphthalein and place flask on a white tile to see the colour change more clearly

  3. Suspend a burette above the conical flask using a clamp stand and clamp and fill the burette with sulfuric acid

  4. Slowly add drops of acid, swirling after each one, until the phenolphthalein indicator turns permanently colourless. This is the end point

  5. Read the volume of acid added from the burette (from the bottom of the meniscus)

Calculations/graphing:

  • see ‘Titration Calculations’