Chemistry

04. Standardisation of an acid solution

  • 00:21 Why is it useful to find the approximate weight of the empty weighing bottle first?
  • 00:46 Why is it not important that traces of solid remain in the weighing bottle?
  • 01:05 Why is it important not to add the whole 250cm3 of water?
  • 01:22 Why is it important to rinse the beaker, stirring rod and funnel?
  • 01:41 Why is it better to use a Pasteur pipette to make the water reach the graduation mark?
  • 01:52 Why is it important to invert the flask several times?
  • 01:52 Why not just shake flask from side to side?
  • 02:02 Why is it important to label all solutions?
  • 02:11 Why is it important to rinse the burette using HCl instead of deionized water?
  • 02:18 Why is it important to remove the small funnel from the burette?
  • 02:25 Why is it important to remove air bubbles from the jet? 
  • 02:30 Why is it important to rinse the volumetric pipette with sodium carbonate solution, and not with water?
  • 02:55 Why is it important not to add too many drops of indicator?
  • 02:51 Why is it important not to blow the liquid out of the pipette?
  • 03:18 Why use a white tile?
  • 03:22 Why is it important to slow the flow rate from the burette as the end-point approaches? 
  • 03:22 How do you know the end-point is close? 
  • 03:26 Why is it important to swirl the flask continually? 
  • 03:51 Why are non-concordant titre values not used to calculate the mean titre?

  • a 3-decimal-place digital balance (minimum 2 decimal place)

  • de-ionised water / distilled water

  • weighing bottle / boat

  • 250 cm³ volumetric flask and funnel

  • 250 cm³ beaker and glass rod

  • labels

  • pasteur pipette

  • anhydrous Na2CO3

  • 50 cm³ burette, burette clamp and stand

  • 25 cm3 bulb / volumetric pipette with safety filler

  • 2 x 250 cm3 conical flask

  • white tile 

  • 0.2 mol dm-3 HCl solution

  • methyl orange indicator

Hazard Risk Control measure

Na2CO3

Irritant - Contact with eyes

Flood eye with tap water (10 min)

See doctor if pain persists

0.2 mol dm-3 HCl solution

Contact with eyes

Flood eye with tap water (10 min)

See doctor if pain persists

Methyl orange indicator

Contact with naked flame

Avoid contact with naked flames