Question

Define and provide examples of the following terms:

a) n-alkanes

b) alkene

c) alkyne

d) saturated

e) hydrophobic

f) aromatic

g) hydrophilic

h) combustion

i) methylene group

j) methyl group

k) common name

l) IUPAC name

m) conformations

n) Newman projection

o) eclipsed

p) staggered

q) gauche conformation

r) anti conformation

s) catalytic cracking

t) cis-trans isomers of a ring

u) chair conformation

v) boat conformation

w) distorted boat

x) half chair conformation

y) axial position

z) equatorial position

aa) chair-chair interconversion

bb) fused ring system

cc) bridged bicyclic compound

dd) bridgehead carbon atoms

Answer 1

a) n-alkanes

These are hydrocarbons (compounds made of carbon and hydrogen only) containing carbon atoms bonded by only single bonds in a straight chain. For example, n-butane has 4 carbon atoms bonded by single bonds in a straight chain. The structure is as shown

CH₃-CH₂-CH₂-CH₃

b) Alkene

There are hydrocarbons containing atleast one C=C (double bond). For example, ethene has two carbon atoms bonded by a double bond as shown

CH₂=CH₂

c) Alkyne

These are hydrocarbons containing atleast one (triple bond). For example, ethyne has two carbon atoms bonded by a triple bond as shown

d) Saturated

A saturated compound is the one in which no more atoms can be added i.e. it has atoms bonded only by single bonds. For example methane CH₄ is a saturated compound, C has valency 4, it is bound by single bonds to each of the 4 hydrogens.

e) Hydrophobic

Hydro means water and phobic means having fear. So hydrophobic substances have fear of water means they are water repelling substances. For example, oil doesn't dissolve in water. It is hydrophobic.