Volumetric flasks are used for the dilution of solutions to a specific volume. They have accurate volume. come in various sizes, from 1 mL to 2 L or more. A typical flask is shown in the figure. These flasks are designed to contain an accurate volume at the specified temperature (20 or 25◦ C) when the bottom of the meniscus (the concave curvature of the upper surface of the water in a column caused by capillary action) touches the line across the neck of the glass. These flasks are marked with “TC” to indicate “to contain.” Fundamentals of Analytical Chemistry by Skoog Advanced analytical chemistry By GD Christian https://en.wikipedia.org/wiki/Volumetric_flask They are directly marked on the face by the manufacturer as to the uncertainty of the container measurement; for example, a 250 mL volumetric flask is “±0.24 mL,” or roughly a 0.1% error. Initially, a small amount of diluent (usually distilled water) is added to the empty flask. Reagent chemicals should never be added directly to a dry glass surface, as glass is highly absorbent. When using a volumetric flask, a solution should be prepared stepwise. Fundamentals of analytical Chemistry by Skoog Advanced analytical chemistry By GD Christian https://www.youtube.com/watch?v=hrvXuX0Ow3s

1. Course Title: Volumetric
Measurements
Course Code: CHM-404
Semmester: 4th E
Lecture: 1

2. Volumetric Measurements

3.  Volumetric flasks
 Uses
 Sizes
 Procedure to use volumetric flask
 Pipets
 Volumetric pipets
 Measuring pipets
 Syringe pipets
 Micropipets
 Buret
 Graduated cylinder

4. A volumetric flask is a flat bottmoed bulb flask with
elongated neck caliberated to contain a precise volume of
liquid at a certain temperature.

5. Uses
 They are used for precise dilution of
solution to certain volume.
 They are used for prepration of
standard solution.
 They are marked as “TC”
to indicate “to contaion”,
an accurate volume at
specified temperature (20 or 25ºC).
TC or to contain
Temperature 20ºC
Volume 1000 mL

6. Procedure to use volumetric flask
 Samll amount of diluent (usually distilled water) is added to
empty flask before addition of reagent chemicals.
 Reagent chemicals never added directly to dry volumetric
flask, as glass is highly adsorbent.
 Diluent is added upto caliberation mark.
 If any droplets of water on flask neck, blot them out with
help of piece of tissue.
 Solution is thoroughly mixed by shaking the flask by keeping
the stopper securely using thumb or palm of other hand.

7. Procedure to use volumetric flask
 Solution is thoroughly mixed by
shaking the flask by keeping the
stopper securely using thumb or
palm of other hand.
 Diluent is added so that the
bottom of meniscus ia at eye level.

8. Sizes
 They are available in different
sizes ranging from 1mL to 2 L
 Accuracy limit, neck height,
flask diamter and
stopper size varies with
variation in size
 A flask of 250 mL
generally has accuracy
limit of “±0.24mL” or
roughly o.1% error.
Different sizes
Accuracy limit of
±0.20
Caliberation mark

9. Classes
 They are available in two
different accuracy classes named as
class “A” and class “B”.
 Class “A” is the highest accurate
class of products,and class
“B” products have
half
accuracy than class “A”.
Class A
Class B
Caliberation
mark

10. Pipet is used to deliver aliquot (certain fraction)
of a solution. They are marked as “TD” or “to
deliver” a specific volume of liquid at a given
temperature.

11. Volumetric pipets
 They have narrow tip
and bulb like expansion
in middle
 Volumetric pipets are used
for accurate measurements.

12. Volumetric pipets
 They are caliberated
to deliver only one volume.
 They have single
graduation mark.
 They are available in different volumes
generally 0.5mL to 25mL.
Different
volumes