Question

Question #2420c

Answer 1

The Kb determines if a compound is a weak base or a strong base. Also the determination of pH or POH can determine if s compound is a strong or weak base.

Explanation:

A strong base has a large number of basic ions OH- in solution. A weak base has a small percentage of basic ions OH - in solution.

Ph 8-10 are weak bases, Ph 11-14 are strong bases.

H+ + OH- = 14

in water H+ = `10^-7` and OH- = `10^-7`

At Ph 13 for example H+ = `10^-13` while OH- = # 10^-1

The total must always equal `10^-14`

OH- `10^-1` means that 1/10 molecules is a OH- ion 10% of the solution that makes it a strong base.

pH 8 means that OH- = `10^-8`

`10^-8` = 1/00000000 of the solution are OH- ions. That makes it a weak base.

Answer 2

The `K_b` determines if a compound is a weak base or a strong base.

Explanation:

A strong base dissociates completely in solution (has a `K_b ≫ 1`).

A weak base dissociates slightly in solution (has a `K_b ≪ 1`).

A base can be a strong base, even if it contributes only a few ions to the solution.

Thus, `"NaOH"` is a strong base because it dissociates completely:

`"NaOH(aq)" → "Na"^+"(aq)" + "OH"^"-""(aq)"`

If you dissolve `10^"-8" color(white)(l) "mol of NaOH"` in 1 L of water, it will contribute only `10^"-8"color(white)(l) "mol"` of `"OH"^"-"` ions, but that is 100 % of what it has to give.

`"NaOH"` is a strong base. Its strength does not depend on its concentration.