Substitution Vs Elimination

Question 1

What is a strong nucleophile?

Answer 1

These are anions that are relatively small molecules that have little difficulties in approaching the carbon atom in the opposite side of the leaving group

Question 2

What is a strong base?

Answer 2

These are anions with high pka values that are relatively large molecules which have difficulty in attacking the carbon atom on the opposite side of the leaving group

Question 3

Why do substitution and elimination compete?

Answer 3

This is because nucleophiles can also act as bases

Also The conditions for SN1 and E1 have similar conditions and SN2 and E2 also have similar conditions

Question 4

Which reacts can tertiary undergo?

Answer 4

Can undergo E2 but not SN2

They can also undergo SN1

Question 5

What reactions can primary and secondary react in?

Answer 5

Can undergo E2 and SN2

Question 6

What determines which product will form with a secondary and primary halogenoalkane

Answer 6

Strong nucleophiles favour the substituted products

Strong bases favour the elimination products

Question 7

How does temperature affect the rate of eleimination and substitution reactions?

Answer 7

Increases the rate of both but favours elimination as E2 has a higher activation energy

Question 8

Why is a small nucleophile favoured in SN1 over E1

Answer 8

This is because it can easily attack a carbocation

Question 9

Why do large bases favour E1 reactions?

Answer 9

This is because it is easier for the large anion to attack a hydrogen on the other carbon atom

Question 10

Which solvent do SN1 and E1 reactions favour?

Answer 10

Polar protic solvents

Question 11

What nature of nucleophile do E2 and SN2 favour?

Answer 11

They favour high concentrations of strong nucleophiles or strong bases are used