How to distinguish hydrogen from methane

How to distinguish hydrogen from methane

The majority of gases have no color and a smell therefore it is very difficult to distinguish them from each other. Besides, they sometimes are in mix with air. Therefore it is necessary to distinguish gases from each other, using chemical methods.


1. Consider that methane and hydrogen have a number of identical properties that complicates process of an otlicheniye them from each other. Both gases are absolutely colourless, have no smell and burn with a flame of identical color. On the physical and chemical properties hydrogen and methane are amphoteric, slightly soluble in water and alcohols, have the smaller density, than air. They have some differences.

2. Pay attention to how hydrogen and methane burn down. In both cases, the flame has bluish color. Mix of any of these gases with air in a small test tube when firing also equally sharply burns down. But methane at combustion emits soot. In order that to check it, take a cold metal plate and bring a flame, and so that it concerned its lower part. If you see soot on one of plates, so methane burns down if is not present - hydrogen. There is it for the reason that at a temperature of 500 degrees methane decays on two components: CH4=C+H2, where With - carbon of which soot consists. It is used for production of black paint under the name "gas soot".

3. Try to distinguish methane from hydrogen on the basis of the fact that for combustion of methane double portions of oxygen, but not half are required as when burning hydrogen.

4. For obtaining the most reliable results carry out combustion of gas in the atmosphere not of air, and chlorine. If in such atmosphere hydrogen burns, the equation of reaction will look as follows: To carry out by H2+Cl2=2HClEsli methane replacement reaction with chlorine at high temperature, chlormethane - gas with a sweetish smell will turn out: CH4=CH3Cl (at t=500 of degrees) However, it is impossible to check a smell of the gas which is turning out as a result of reaction as in both cases it will be poisonous. Therefore it is necessary to set fire to it again, this time - in the air atmosphere. If gas burns with a characteristic green flame, so it is chlormethane and if usual - chlorohydrogen.

Author: «MirrorInfo» Dream Team