Quiz - Alkanes | Alkanes

1

Which one of the following statements regarding alkanes is correct?

Alkanes are polar molecules

All alkane carbon atoms are sp3 hybridized

Alkanes are soluble in water

Alkanes have high boiling points

2

How many groups of equivalent hydrogen does the pentane have?

1

2

3

4

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3

The alcohol of 2-methylpentan-2-ol is:

primary

secondary

tertiary

quaternary

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The alcohol chemical function is on a carbon attached to 3 other carbon atoms ⇒ it is a tertiary alcohol

4

What is the correct IUPAC name of (CH3)2CHCH2CH(CH2CH2CH3)2?

1,1-dimethyl-3,3-dipropylpropane

1-isopropyl-2-propylpentane

2-methyl-4-propylheptane

6-methyl-4-propylheptane

1) Longest chain: 7 carbon atoms ⇒ heptane
2) 1 methyl substituent + 1 propyl substituent
3) The left end is the closest to a subst.: number the C atoms from the left to the right
4) 2-methyl-4-propylheptane

4

What is the first step of the halogenation of alkanes?

Heterolytic cleavage of the dihalogen

Homolytic cleavage of the dihalogen

Propagation

Chain termination

Radical chain reactions proceed in 3 stages: initiation (homolytic cleavage of the Cl-Cl bond), propagation and termination (radical-radical combination)

5

How many products do you expect with the halogenation of methylpropane?

1

2

3

4

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6

What is the most stable radical?

Primary radical

Secondary radical

Tertiary radical

Quaternary radical

The stability of radicals increases along the series from primary to secondary to tertiary (hyperconjugation). There are no quaternary radicals since carbon atoms cannot have more than 8 electrons in their valence shell