Organic Chemistry - exam corrections Flashcards
Explain why E-Z isomerism exists in But-2-ene?
it has a double bond which restricts rotation
it has two different groups on both carbons either side of the double bond
Outline how 2-chloro-2-methylbutane could be prepared in a lab?
- 2-methylbutan-2-ol
- add PCl5
- ROOM TEMP
Define ‘nucleophile’
a species attracted to areas of positive charge and an electron pair donor
Halogenoalkane + water –>
What reaction is this NOT and why is it not
alcohol + hydrogen halide
IT IS NOT THE halogenoalkane + aq potassium hydroxide reaction because in this case a whole WATER MOLECULE is the nucleophile, not just an OH-
Why is ethanol used as a solvent in the hydrolysis of halogenoalkanes experiment?
it is a solvent for both the halogenoalkane AND the silver nitrate
ionic equation for formation of silver bromide
Ag+ (aq) + Br- (aq) —–> AgBr (s)
What can be used to dissolve silver bromide?
concentrated ammonia
what tests for the presence of aldehydes/ketones?
2-4dnph turns orange –> green/blue in the presence of the C=O in aldehydes or ketones
conditions for producing primary amines from halogenoalkanes
concentrated ammonia in ethanol in a sealed test tube at high pressures
Why can you not heat this mixture (ammonia in ethanol for the primary amine mechanism) under reflux?
the ammonia would escape up the condenser as a gas
When making primary amines from halogenoalkanes and ammonia how do you make sure the primary amine is the major product?
to make sure the primary amine is a major product you use excess ammonia
Why are sigma bonds stronger than pi bonds?
there is a good overlap of S orbitals in sigma bonds but in pi bonds there is a poorer sideways overlap of the p orbitals
How to tell if something is polar
put a charged object near a jet of the liquid. If the jet is deflected then the liquid is polar
H2O2 –>
H2O2 —> H20 + 1/2O2
Free radical definition
species with an unpaired electron formed by homolytic fission
