Part 1: Solubility and Miscibility a) Test the solubility of the following solids in solvents as follows: Typical laboratory procedure:To each test tube add a few granules of solid followed by solvent (1 mL). Stopper/bung and shake for 20-30 seconds (without inverting – keep the lid dry), then leave to settle.
-Potassium iodide in i) water ii) hexane
-iodine in i) water ii) hexane iii) dichloromethane
Video 1: Solubility of potassium iodide in water
Video 2: Solubility of potassium iodide in hexane video
Video 3 Solubility of iodine video
Water Hexane Chloroform
KI
Observation:
X
Conclusion:
X
I2
Observation:
Conclusion:
Notes on observations, technique and lab practice for Iodine video:
Notes on observations, technique and lab practice for potassium iodide video:
b) Test the following solvent mixtures for miscibility by adding 1 mL of each solvent in a test tube, sealing the tube, shaking to mix (10 seconds), and leaving to settle (10 seconds).
Video for water with ethanol, hexane and 1-butanol
Water/Ethanol Water/Hexane Water/1-butanol
Observation:
Conclusion:
Is there a phase boundary? Where layers form, state in the table which solvent forms the upper/lower layer.
How could you confirm your answer with KI or iodine?
Where does the colour in the video reside? What does this prove about the solvents’ relative density and polarity?
Part 2: Using a burette to see the effect of an electrical field on liquid streams
Typical laboratory procedure:
-Locate the four set up burettes (fume cupboard, far end of N219) containing water, ethanol, petroleum ether and formic acid.
-Statically charge up the polythene rod by rubbing it on a piece of cloth
-Open the burette tap to set up a slow but steady stream of falling liquid, collecting in the beaker.
-Move the rod to about 1-2 cm away from the falling liquid stream (no closer!).
-Note what happens (if anything) to the path of the stream.
-Repeat the experiment for the other liquids.
Watch the following video and detail your notes, observations and conclusions below:Water and hexane with static charge video Water hexane
Observation:Conclusion:Notes on video:What does the direction of liquid fall tell you about the polarity and intermolecular forces in the liquid in each case?
Part 3: Reactivity of Functional Groups
a) Bromine can be used to test for functional groups. Watch the following video of bromine being added to an alkane and an alkene. Watch the following video and answer the questions below:Alkanes and alkenes with bromine video
What happens when bromine is added to the alkane?What happens when bromine is added to the alkene?Using hexene as an example, explain what happens when bromine is added to a sample of each – explain in words along with a drawn curly arrow mechanism.b) Tollens Test
The Tollens test, also known as the silver mirror test, can be used to distinguish between functional groups. Watch the following video and answer the questions below:Tollens Test (Silver-Mirror Test)Notes on video:What is the Tollens test used for?What compounds/solvent(s) does the Tollens test consist of?Why are known positives/negatives used?