alchols

Question 1

alchols are produced industrailly by

Answer 1

hydration of alkenes in the presences of acid catalyst (H3PO4)

Question 2

ethanol is produced industrially by … and why

Answer 2

fermentation of glucose
cheaper than hydration as carried out at lower temp but has to be done in batches so slower process with a lower % yield
glucose –> ethanol + carbon dioxide
yeast must be present

Question 3

how is biofuel formed and why is it used

Answer 3

separating of ethanol by fractional distillation. it is said to be carbon nuetral as the carbon given out when burned is equal to the carbon taken in by crops during the growing phase

Question 4

environmental issues linked to biofuels use

Answer 4

destruction of crops
transportation of crops

Question 5

classification of alchols

Answer 5

primary - carbon bonded to OH is bonded to one other C
secondary - carbon bonded to OH is bonded to 2 other C
teritary - carbon bonded to OH is bonded to 3 other C

Question 6

oxidation of primary alcohols

Answer 6

forms aldehydes
reagent: acidified potassium dichromate [O]
conditions: heat under distillation

Question 7

oxidation of aldehyde

Answer 7

forms carboxyllic acid
reagent :acidified potassium dichromate [O]
conditition: heat under reflux

Question 8

oxidation of secondary alchols

Answer 8

forms ketones
reagent: acidified pottasium dichromate
condistion : heat under reflux or distillation

Question 9

primary alchol -> carboxylic acid

Answer 9

oxidation
reagent : acidified potassium dichromate[O]
condition: heat under reflux, excess oxidising agent

Question 10

oxidation of tertiary alchols

Answer 10

cannot be easily oxisied

Question 11

explain how the method used to oxide a primary alcohol determines what the product obtained is

Answer 11

under distillation so aldehydes not mixed back into oxidising agent instead separated to prevent further reaction to carboxylic acid that would take place if under reflux

Question 12

observation of colour change when alchol oxidised

Answer 12

orange –> green

Question 13

chemical test to distinguise between aldehydes and ketones

Answer 13

fehlings solutiuon
aldheyde : brick red precicitate
ketone: NVC
tollens reagent
aldehyde: silver mirror forms
ketone: NVC

Question 14

alchol –> alkene

Answer 14

elimination
catalyst : hot conc H2SO4 OR AlO3
condition: 600K
lone pair on O in R-OH attracted to &+ on H causing R-OH2 where O is +, C-O is broken removing water resulting in C-C+ electrons from C-H to C-C+ forming C=C and H+
H+ reformed therefore catalyst

Question 15

importanct of alchol-> alkene elimination reaction

Answer 15

means addition polymers can be produced from fermentation without need for crude oil( a non-renewable resource)

Question 16

test for carboxylic acids

Answer 16

Na2CO3
effervescence