Answer:
meter the mean free path of hydrogen atoms in interstellar space.Explanation:
The mean free path equation is given as:

Where"
d = diameter of hydrogen atom in meters
n = number of molecules per unit volume
We are given: d = 100 pm = 



meter the mean free path of hydrogen atoms in interstellar space.
1-pentyne consists of a carbon chain of 5 carbons one with a triple bond. 1-octyne is a carbon chain of 8 carbons with a triple bond at some point. It is known that the longer the carbon chain the higher the boiling point since more energy will be required to break the bonds between carbons. Based on this it is predicted that 1-octyne will have a higher boiling point than 1-pentyne.
<span>There are only three stereoisomers of 1,2-dimethylcyclopentane. As there are only two chiral carbons, so the maximum number of stereoisomers is 4, but two are the same meso-compound which means that there are only 3.</span>
Answer: C
Explanation:
Some poly nuclear aromatic hydrocarbons are not carcinogenic in themselves. However, when these are made to interact with living cells, enzymes in the cells could convert the polynuclear aromatic hydrocarbon into a carcinogenic material such as benzo-[a]-pyrene. This can now interact adversely with the deoxyribonucleic acid of living cells leading to genetic mutation, that is, irreversible changes in the genes of organisms.