Volumetric Analysis – Titration Apparatus
Main Apparatus Used:
1.
2.
3.
4.
5.
Graduated Cylinder
Volumetric Flask
Pipette
Burette
Conical Flask
1. Graduated Cylinder:
- Not particularly accurate – should only be used to measure out approximate volumes of
liquids
- Before using should be rinsed out with deionised water
2. Volumetric Flask
General:
- designed to contain a definite volume of solution
- long thin neck with graduation mark allows volume of solution to be adjusted
Accurately)
When using a volumetric flask:
- rinse with deionised water
- make sure it is at room temperature (calibrated at 20o C
- make up to 5cm3 away from mark with deionised water and then add the last 5cm3
with a dropper
- read from the bottom of the meniscus at eye level, making sure bottom of
meniscus is level with calibration mark
- mix by inverting 20 times to ensure solution homogeneous
3. Pipette
General:
- designed to deliver an exact volume of solution
- pipette is filled by using a pipette filler to draw the solution above graduation mark,
liquid is then allowed to run out until bottom of meniscus is level with graduation
mark.
When using a pipette:
- rinse with deionised water (remove impurities)
- rinse with solution it is going to contain (to remove deionised water)
- fill using a pipette filler
- read from the bottom of the meniscus (should be level with calibration mark)
- empty into conical flask and touch tip against the side (prevents splashing)
- DO NOT force last drop out pipette is calibrated to allow for this drop.
4.Burette
General:
- long narrow glass tube closed at the bottom by means of a tap – graduations on
burette read downwards
- before using burette check tap to make sure it turns freely
Use of Burette:
- rinse with deionised water
- rinse with solution it is going to contain
- fill burette using a funnel and remove funnel (as drops may fall from it giving a false
reading)
- Remove the air bubble from the tip by opening the tap and allowing liquid to fill part
of burette below tap
- ensure burette is clamped VERTICALLY!!!!
- Adjust the level of liquid in the burette until the bottom of the meniscus is on the
zero mark (read at eye level)
- DO NOT put NaOH in burette as it may react with glass of burette or block tap
5. Conical Flask (Titration Flask)
General:
- designed so that it may be swirled without the liquid splashing out
- shape allows any drops of solution sticking to side of flask to be easily washed
Down
Use of Conical Flask:
- rinse out with deionised water ONLY (if washed out with solution it is to
contain any drops of solution left in the flask would add to the EXACT volume
added from pipette thus giving inaccurate results.
- place on a white tile
- add 2-3 drops of indicator (all indicators are either weak acids or bases and so
too much may affect the results)
- wash down any drops on side of flask with deionised water
Titration Method (Brief):
 Add 2-3 drops indicator
 Mix well
 Add solution from burette – drop by drop towards end point (end point is point
at which reaction is complete shown by colour change)
 Do 1 rough and two accurate titrations
 Two accurate should be within 0.1cm3
 Average the two accurate titrations
 Identify the standard
 Identify the standard solution (solution of known concentration) use in
calculation of concentration of second solution