Iodine and sodium hydroxide help differentiate between methanol and ethanol. But experimenting with these substances requires care, because both methanol and ethanol are hazardous. Ethanol is highly flammable, and methanol is both flammable and toxic; always wear safety goggles and gloves when experimenting with them. Only a few drops of each liquid are needed to conduct an experiment. Work slowly and carefully. Use a separate eyedropper, or pipette attachment, to move each liquid from the storage container to a test tube.
Wear safety goggles and snug-fitting gloves to prevent accidents when working with delicate instruments.
Place the clean test tubes in a test-tube holder to prevent spills. If you are working with a partner, you may hold the test tubes in your non-dominant hand, but this is not as safe.
Use the eyedropper to extract a small sample of ethanol from the container. Do this in an empty sink to prevent spills.
Add 10 drops of ethanol directly to a test tube. Clean the eyedropper and place it on a towel; do not put it back in the ethanol. Reseal the ethanol container and remove it from the sink.
Place the methanol container in the sink and use the methanol eyedropper to add 10 drops of the liquid to the other test tube. Rinse the methanol eyedropper and set it aside, separate from the ethanol eyedropper.
Add 25 drops of Iodine to each test tube.
Add 10 drops of sodium hydroxide to each test tube. Clean the eyedroppers the same way you did for the other substances.
Swirl each test tube gently until the substances mix together.
Wait for two minutes, then observe the changes in the test tubes. Ethanol will retain a yellowish color and have a strong antiseptic-like smell, while methanol will become clear again.
