amines

Question 1

what are amine

Answer 1

derivatives to ammonia one or more hydrogen are replaced by an alkyl group

Question 2

why are they good as intermediate synthesis

Answer 2

as they are very reactive

Question 3

what shape is ammonia

Answer 3

pyramidal molecules with a bond angle of 107 as a result of the lone pair of the electron

Question 4

if amine are polar what does this mean

Answer 4

there is a difference in electronegativity between nitrogen and hydrogen so can form hydrogen bonding

Question 5

compare the hydrogen bonding in water and in ammonia

Answer 5

hydrogen bonding is stronger in alcohols as oxygen is more electronegative than hydrogen

Question 6

what are the states like in room temperature

Answer 6

shorter chains are gases at room temperature, and longer ones are volatile liquids and have a fishy smell

Question 7

what are the solubility like

Answer 7

shorter amines are soluble in solvents

Question 8

why

Answer 8

because they form hydrogen bonds and the hydrogen bonds in the amine and water can interact

Question 9

what importance is the lone pair

Answer 9

it can form a bond with the h+ hen acting as a base

form a bond with a deficient carbon atom acting like a nucleophile

Question 10

how do amine react with acids

Answer 10

they react to form salts

Question 11

describe the products

Answer 11

they are ionic compounds that can crystallise as the water evaporates

Question 12

what if a base is added to the salt

Answer 12

it removes the proton and regenerates the soluble amine

Question 13

what is the base strength dependent on

Answer 13

how readily it will accept a proton

Question 14

what do alkyl groups do

Answer 14

they release electron towards the nitrogen which is called the inductive effect

Question 15

what does the inductive effect do to nitrogen

Answer 15

increases the electron density o nitrogen and makes it a better electron donor

Question 16

why are tertiary amines not stronger than secondary amines

Answer 16

they are less soluble in water

Question 17

how are primary amines formed

Answer 17

when ammonia reacts with halogenoalkane in nucleophilic substitution

Question 18

how does a quaternary salt form

Answer 18

tertiary amine will react with halogenoalkane

Question 19

why is this not an appropriate way to prepare an amine

Answer 19

as a mixture of primary/secondary and tertiary amine are formed that needs to be separated

Question 20

how to ensure a larger yield of primary amine

Answer 20

using excess ammonia

Question 21

whyat is the purer way of forming primary amine

Answer 21

reducing nitrile group to an amine group using a platinum or nickel catalyst with hydrogen

Question 22

how does nitrobenzene form phenylamine

Answer 22

it is reduced by reacting with tin and hcl

Question 23

as hcl is used what can also be form

Answer 23

the ammonium salt

Question 24

how do we free up the primary amine

Answer 24

we react it with sodium hydroxide to form sodium chloride and phenylamine

Question 25

what are quaternary amine used for

Answer 25

industrially to manufacture hair fabric and conditioners

Question 26

why do they form cations

Answer 26

as they have a long hydrocarbon chain and a positively charged organic group

Question 27

what do both wet hair and wet fabric do

Answer 27

pick up negative charges on their surface

Question 28

so what does positive cations do

Answer 28

attract the negative charges to the wet surface forming a coating to prevent build up of static electricity

Question 29

what does this keep

Answer 29

the surface of the fabric smooth and prevent flyaway hair in conditioner

Question 30

why are they called cationic surfactants

Answer 30

because in aqueous solutions the ions cluster with their charged ends in water and their hydrocarbon tails on the surface