Identify the most and the least basic compound in each of the following sets. Leave the remaining answer in each set blank. a) Sodium acetate: Ammonia: Sodium ethoxide: b) Sodium acetate: Sodium chloroacetate: Sodium fluoroacetate: c) Sodium acetate: Sodium methoxide: Sodium phenoxide:

The correct answer is -

a) Sodium acetate: least Ammonia: Sodium ethoxide: most

b) Sodium acetate: most Sodium chloroacetate: Sodium fluoroacetate: least

c)  Sodium acetate: least Sodium methoxide: most Sodium phenoxide:

Explanation:

A) In this case the basicity can be found by the stability of the base, Sodium acetate is the most stable base due to resonance stabilization of acetate anion. Sodium acetate is the least basic as the lone pair of electrons involved in the resonance here. An ethoxide ion has more electrons to donate an electron pair easily.

Thus, the correct answer is - Sodium acetate is the least basic while sodium ethoxide is the most basic.

B) Fluroacetate gives a very strong acid and the acetate gives the least strong acid among all three as described in case of a), thus, the most basic is acetate and the least is fluoroacetate.

]C) comparing the acidity of the acids formed by the addition of a proton to the anions is an easy and correct way to find the basicity of compounds.

Acetate ion adds a proton ⇒ acetic acid

methoxide adds a proton ⇒ methanol

phenoxide ion adds proton ⇒ phenol

As it is known that the stronger the acid, the weaker is the conjugate base formed by the loss of the proton.

acetic acid is the strongest acid because it can easily give up its proton to form acetate. Methanol is the weakest among all three and hence methoxide anion is the strongest base.

Thus, the correct answer is - sodium acetate is the least basic while sodium methoxide is the most basic.