Skip to main content

Fractional Crystallization/ Fractional crystallization of all salts/ Fractional crystallization of NaCl and NH4Cl.

 Fractional crystallization of NaCl and NH4Cl


Fractional Crystallization

Principle:

The impurities are more soluble when the temperature increases in the liquid medium. The refining materials are more likely to get easily in fractions. It is all done due to the solubility differences.

Material Required:

China dish, wire gauze, filter paper, tripod stand, beaker, stirrer, Bunsen burner, distilled water, funnel, weight machine, solution of two salts which have to separate by crystallization (i.e. NaCl and NH4Cl).

The technique of preparing NaCl and NH4Cl solution or salt solution:

Take 4g of NaCl and 7g of NH4Cl (you may use the salts of your own choice that you want to crystallize). Add the two in distilled water. And mix them at room temperature. The amount of distilled water is 15mL.

Procedure:

  •       Take the china dish and pour the solution of two salts into it.

·      Put the filled china dish on the wire gauze which is already present on a tripod stand.

·      Turn on the burner with a light flame.

·      Stirrer the solution regularly.

·      When the solution becomes too hot and boil remove it from the flame.

·      Then allow it to cool and then filter it through filter paper (by folding filter paper through 1 by 3 and placing it in the glass funnel by damping and its tip is directly in the beaker).

·      You will see that the crystals are filtered on the filter paper as they are of NaCl because it is less soluble in the distilled water than NH4Cl.

·      The filtrate that is collected in the beaker is again put on the flame, and allow the crystals to dry.

·      Again filter the remaining solution and dry the crystals repeat it many times until no filtrate is left behind.

·      Collect all the crystals on each filter paper.

o  First weight the filter paper

o  Then weigh the filter paper with crystals on the weighing machine.

Calculation of Yield:

Weight of filter paper = 0.2 g

Weight of crystals = 2.9 g

Weight of Total NaCl = 4g

Amount of NaCl we lost (4g – 2.9g) = 1.1g

Result:

The yield we get is 2.9g.





Comments

Post a Comment

Popular posts from this blog

Synthetic Application of Arynes

  Introduction Arynes are reactive intermediates derived from substituted arenes which participate in some aromatic nucleophilic substitutions and some cycloaddition reactions. It is non isolable very reactive species with the hexagonal planar ring structure with six pi delocalizing and 2 additional pi electrons. The additional 2 pi electrons do not affect the aromatic character of ring as it does not interfere with the Huckel number. Arynes are so highly reactive that they exist as stable species only at very low temperatures, e.g., 8 K for benzyne. Arynes may be derived from substituted benzenes, fused arenes and pyridines. Structure of Benzyne The sp 2 orbitals involved in the ‘triple bond’ are at 90 o to the p-orbitals of the aromatic pi-system Instead of an overlap between two 2p orbitals (as in an alkyne) the “triple bond” is formedthrough overlap of two adjacent sp2 orbitals in the plane of the ring (i.e., at right angles to, and completely independently of, the aromatic
Post a Comment
Read more