Variable
benzene
pentenes
2-methylpropane
n-pentane
m-p-xylene
propene
cis-2-pentene
3-methylpentane
o-xylene
ethyne
n-butane
trans-2-butene
2-methylpropene
n-heptane
1-3-butadiene
2-methylpentane
1-butene
toluene
n-hexane
ethene
ethane
cis-2-butene