Question

Rank the following species in order of increasing basicity. Rank bases from strongest to weakest. To rank items as equivalent, overlap them. I think I almost have them in order based on pKb values and conjugate pair strengths.

-NH2 OH- NH3 CH3O- CH3COO- HSO4- H2O

Answer 1

Species are ranked from strongest to weakest base as CH3O-, NH2-, NH3, CH3COO-, OH-, H2O, and HSO4-, based on criteria such as ionization in water, pKb values, charge distribution, and the strength of their conjugate acids.

Step-by-step explanation:

The question involves ranking species in order of increasing basicity, from strongest to weakest. Basicity is a measure of how well a substance can accept protons (H+ ions), and it is often represented by the pKb value. The higher the pKb, the weaker the base.

Considering the provided species, we can rank them as follows, from strongest to weakest base:

1. CH3O- (Methoxide ion)
2. NH2- (Amide ion)
3. NH3 (Ammonia)
4. CH3COO- (Acetate ion)
5. OH- (Hydroxide ion)
6. H2O (Water)
7. HSO4- (Hydrogen sulfate ion)

This ranking is determined by looking at their respective pKb values, the type of atom bearing the negative charge, the ability to delocalize that charge, and the corresponding strength of their conjugate acids. Methoxide ion (CH3O-) and amide ion (NH2-) are strong bases that are known to completely ionize in water, while hydrogen sulfate ion (HSO4-) is a very weak base, being the conjugate base of a strong acid (H2SO4). Ammonia (NH3) is a weak base. Groups like CH3COO- (acetate ion) and OH- (hydroxide ion) have intermediate strength, positioned in the middle of the range.