5.8 - Acid-Base Titrations

• phenolphthalein

  colour in acid: colourless

  colour in alkali:

  pH range over which colour change occurs: 8.2-10.0
• methyl orange

  colour in acid: red

  colour in alakali: yellow

  pH range over which colour change occurs: 3.2-4.2
• methyl red

  colour in acid: yellow

  colour in alakali: red

  pH range over which colour change occurs: 4.8-6.0
• bromothymol blue

  colour in acid: yellow

  colour in alkali: blue

  pH range over which colour change occurs: 6.0-7.6
• measuring equipment

  burette

  pipette
• burette

  measure different volumes

  lets you drop solution drop by drop

  usually measure volume of acid with it
• (glass) pipette

  measure only one volume of solution

  usually measure volume of alkali with it
• strong acids and alkalis

  fully ionise in solutions
• weak acids and alkalis

  partially ionise in solutions