Alcohols Flashcards

1
Q

What is the functional group of an alcohol?

A

-OH

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2
Q

What is the general formula of an alcohol?

A

CnH2n+1 OH

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3
Q

What type of intermolecular forces do alcohols have?

A

Hydrogen bonding due to the electronegativity difference in the OH bond

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4
Q

How do alcohols melting and boiling point differ to other hydrocarbons of similar chain lengths?

A

Alcohols have higher bp because of its strong hydrogen bonding but as chain length increases, the contribution of the -OH decreases

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5
Q

Are alcohols soluble in water?

A

Alcohols can form hydrogen bonds with water molecules

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6
Q

How do you classify alcohols as primary, secondary and tertiary?

A

One alkyl group = primary
Two alkyl groups = secondary
Three alkyl groups = tertiary

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7
Q

What forms if you partially oxidise a primary alcohol?

A

Aldehyde (-COH)

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8
Q

What conditions are needed to partially oxidise a primary alcohol?

A

Dilute H2SO4 and K2Cr2O7, distil product as its produced with gentle heating

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9
Q

What forms if you fully oxidise a primary alcohol?

A

A carboxylic acid

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10
Q

What conditions are needed to fully oxidise a primary alcohol?

A

Concentrated H2S04 and K2Cr207, heated strongly under reflux

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11
Q

What forms if you oxidise a secondary alcohol?

A

A ketone

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12
Q

What conditions are needed for the oxidation of a secondary alcohol?

A

Concentrated H2SO4 and K2CR207, strongly heated under reflux

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13
Q

Is it possible to oxidise a tertiary alcohol?

A

No

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14
Q

What other by-product is formed whenever an alcohol is oxidised?

A

H2O

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15
Q

What is the colour change of K2Cr207?

A

The orange dichromate ions (CR207 2-) is reduced to green chromium ions (Cr3+)

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16
Q

What is a dehydration reaction?

A

A reaction where water is lost to form an organic compound

17
Q

What are the products of a dehydration reaction of alcohol?

A

Alkene and water

18
Q

What conditions are required for the dehydration of alcohol?

A

Concentrated acid (H2SO4 or H3PO4) and 170 degrees

19
Q

What happens in a substitution reaction?

A

The -OH is substituted by a halide, so the alcohol is transformed into a haloalkane. The reaction requires H2SO4 and a sodium halide (NaBr)

20
Q

Do alcohols have a lower or higher volatility than alkanes and why?

A

Lower because the strong hydrogen bonds needs to be broken to change state