Question

Experiment 4C Directions

Obtain three test tubes, each containing two layers. For each tube, you will be told the identity of the two layers, but you will not be told their relative positions. Determine experimentally which layer is organic and which layer is aqueous. Dispose of all thesemixtures into the waste container designated for halogenated organic wastes. After determining the layers experimentally, look up the densities of the various liquids in a handbook to see if there is a correlation between the densities and your results.

The three mixtures will likely be (1) water and n-butyl chloride, (2) water and n-butyl bromide, and (3) n-butyl bromide and saturated aqueous sodium bromide.

Experiment 4C Extraction Questions:

1. For each of the three mixtures, report which layer was on the bottom and which one was on the top. Explain how you determined this for each mixture.

2. Record the densities for the liquids given in a handbook.

3. Was there a correlation between the densities and your results? Explain.

Need help in BOLD.

Answer 1

The three mixtures will likely be :

The position of 2 layers depends upon their densities. The one which is lighter will be in the upper layer and the one which is heavier will be in the lower/bottom layer. But during extraction the solute dissolved in the respective layers may increase the density of solution.

In order to determine which layer nature whether it is aqueous layer or organic layer. Initially in order to determine first layer are separated into different flasks then water is added to both the layers. If the solution is aqueous layer then water dissolves and can be confirmed as aqueous layer.

If the water is added to the other solution which separates as the layer then it can be confirmed as organic layer.

(1) water and n-butyl chloride : Density of n- butyl chloride is 880 kg/m³ . and density of water is 1000 kg/m³ . As, water is denser than the n- butyl chloride (organic layer) it will be in lower/bottom layer. Whereas n-butyl chloride is in the upper layer.

(2) water and n-butyl bromide : Density of n- butyl chloride is 1.27 g/cm³ and density of water is 1 g/cm³ . As, water is denser than the n- butyl bromide (organic layer) it will be in lower/bottom layer. Whereas n-butyl bromide is in the upper layer.

(3) n-butyl bromide and saturated aqueous sodium bromide : Density of n- butyl chloride is 1.27 g/cm³ and density of saturated aqueous sodium bromide is 2.18 g/cm³ . As, saturated aqueous sodium bromide (aqueous layer) is denser than the n- butyl chloride(organic layer) it will be in lower/bottom layer. Whereas n-butyl chloride is in the upper layer.

The correlation between the densities and the result is that the layer which is the solution which is lighter in dense will be in upper portion and the other layer which is heavier is in lower portion.