What is a Kjeldahl flask used for?
Kjeldahl flasks are round bottom flasks with long wide necks that are used in Kjeldahl method for quantitative determination of sample nitrogen content. Kjeldahl flasks are typically manufactured from borosilicate glass, which is resistant to heat and chemicals.
What liquid is used in Kjeldahl flask?
The end of the condenser is dipped into a known volume of standard acid (i.e. acid of known concentration). A weak acid like boric acid (H3BO3) in excess of ammonia is often used. Standardized HCl, H2SO4 or some other strong acid can be used instead, but this is less commonplace.
How does a Kjeldahl apparatus work?
Kjeldahl. The method consists essentially of transforming all nitrogen in a weighed sample into ammonium sulfate by digestion with sulfuric acid, alkalizing the solution, and determining the resulting ammonia by distilling it into a measured volume of standard acid, the excess of which is determined by titration.
What is the difference between volumetric flask and Florence flask?
Florence flask — a flask with a round body and one longer neck without a ground glass joint. Volumetric flask — a flask used for preparing liquids in very precise volumes. It is a flask with a pear-shaped body and a long neck with a line on it which marks the standard volume it can contain.
What is the distillation flask?
Distilling flasks are used to separate mixtures of two liquids with different boiling points. Flask design typically features a distillation column in the form of a long neck, a side arm that facilitates condensation, and a round bottom for uniform heat distribution.
Which indicator is used for to estimation of available N in soil?
The Kjeldahl method is used to determine the nitrogen content in organic and inorganic samples. For longer than 100 years the Kjeldahl method has been used for the determination of nitrogen in a wide range of samples.
What’s the purpose of Florence flask?
The Florence flask is characterized by a long neck and rounded bottom with a flat base. It is useful as a reaction vessel as well as for heating solutions.
Which is more accurate graduated cylinder or volumetric flask?
The volumetric flask is the most accurate, but it only measures 1 volume—in this case, 100mL. If you need to measure other volumes besides those on volumetric flasks, then the graduated cylinder is the best tool. The beaker is pretty accurate, and you can easily stir and heat chemicals in it.