Question

Rank the following in order from strongest base to weakest base:

Short answer

The equilibrium favors reactants should be strong acid and strong base and the products should be weak acid and weak base.

^-NH₂ is a stronger base than the acetylide ion that is formed because NH₃ is a weaker acid than a terminal alkyne. The weaker acid has the stronger conjugate base. Therefore, an amide ion can be used to remove a proton from a terminal alkyne to prepare an acetylide ion.

If hydroxide ion is used as the base, the reaction will strongly favor reactants because hydroxide ion is a much weaker base than the acetylide ion.

Step-by-step solution

One example

The equilibrium favors reactants should be strong acid and strong base and the products should be weak acid and weak base.

^-NH₂ is a stronger base than the acetylide ion that is formed because NH₃ is a weaker acid than a terminal alkyne. The weaker acid has the stronger conjugate base. Therefore, an amide ion can be used to remove a proton from a terminal alkyne to prepare an acetylide ion.

If hydroxide ion is used as the base, the reaction will strongly favor reactants because hydroxide ion is a much weaker base than the acetylide ion.

Acid strength

Final answer

a)sp >sp² >sp³

This is the electronegativity order sp is most electronegative. So ethyne is stronger acid than ethene and ethene is stronger acid than ethane. Hence we can say that ethane is stronger base than ethene and ethene is stronger base than ethyne.

b) It depends on the pk_avalues.