# Chem – College: Matchmaking Between Acidic and Base Equilirium Constants (Ka and you may Kb)

Chem – College: Matchmaking Between Acidic and Base Equilirium Constants (Ka and you may Kb)

When you are given multiple Ka or dabble Kb values (like Ka step one , Ka dos , Ka step step three ), you can also combine them together into an overall Ka or Kb by multiplying them together. The equations below display what I mean.

If Mg(OH) 2 has a Kb 1 of 0.3 and a Kb 2 of cuatro.5 * 10 -3 what is the over all Kb value?

## When the Be(OH)

If H 3 PO 4 has a Ka 1 of 2.8 * 10 -3 and a Ka 2 of 7.1 * 10 -6 . 3 if the overall Ka is 7.75 * 10 -17 ?

Answer: ( 2.8 * 10 -3 ) * ( 7.1 * 10 -6 ) * Ka 3 = 7.75 * 10 -17

If Al(OH) 3 has a Kb 1 of 0.04 and a Kb 2 of 5.1 * 10 -4 what is the over all Kb value?

If H 2 SO 4 has a Ka 1 of 15 and a Ka 2 of 2.0 * 10 -2 . Then what is the over all Ka value?

If H 3 PO 3 has Ka 2 of 4.7 * 10 -5 and a Ka 3 of 2.3 * 10 -8 . 1 if the overall Ka is 5.5 * 10 -16 ?

Answer: Ka1 * (4.7 * 10 -5 ) * (2.3 * 10 -8 ) = 5.5 * 10 -16 — Ka1 = 5.09 * 10 -4

2 has a Kb 1 of 3.6 * 10 -4 and an overall Kb of 8.2 * 10 -12 what would be the Kb 2 ?

Answer: (3.6 * 10 -4 ) * Kb 2 = 8.2 * 10 -12 — Kb 2 = 2.24 * 10 -8

As it happens that Ka and you may Kb is actually connected with you to other during the a formula. It algorithm makes you move out-of Ka to Kb and you may vise versa. The latest formula try found less than .

The fantastic thing about so it formula will it be also enables you in order to anticipate if some thing is an acid or a bottom . How you can figure if things try an acidic or base by their Ka otherwise Kb value should be to evaluate it with the harmony constant to possess liquid as with the newest picture less than.

In the event the Ka turns going to become a bigger amount than this new Kb then the toxins could well be an acidic.

If for example the Kb converts about to become a larger amount than just the brand new Ka then agents was a bottom.

Supply the Kb and you can share with if the chemicals try an acidic or foot if it features an excellent Ka regarding 2.cuatro * ten -six .

Answer: Acidic (Ka was bigger than Kb), Kb = 10 -14 / 2.cuatro * 10 -six = 4.17 * ten -9

Allow the Ka and give whether or not the chemical substances was an acidic otherwise foot if this possess good Kb away from step three.5 * 10 -cuatro .

Answer: Legs (Kb are bigger than Ka), Ka = ten -fourteen / step three.5 * 10 -4 = dos.86 * 10 -eleven

Provide the Kb and give whether the chemicals are an acidic otherwise ft when it enjoys good Ka out-of cuatro.step three * 10 -nine .

Answer: Ft (Kb is actually larger than Ka), Kb = 10 -14 / 4.3 * ten -nine = 2.32 * ten -6

Give the Ka and you can tell if the agents was an acid or foot in the event it has good Kb away from 8.9 * ten -eleven .

Answer: Acid (Ka was larger than Kb), Ka = 10 -14 / 8.nine * ten -11 = step one.a dozen * 10 -4

Allow the Kb and you can give whether or not the toxins is actually an acidic or ft when it possess good Ka out of seven.2 * ten -9 .

Answer: Ft (Kb are bigger than Ka), Kb = 10 -14 / seven.2 * ten -nine = 1.38 * ten -6

Allow the Ka and tell whether the chemical are an acid or ft if it has an effective Kb regarding 4.dos * ten -12 .

Answer: Acid (Ka is larger than Kb), Ka = 10 -14 / cuatro.dos * ten -eleven = 2.38 * 10 -4

Provide the Kb and you can share with perhaps the chemical compounds is actually an acidic or foot if it have a beneficial Ka out of 3.cuatro * 10 -step 3 .

## Upcoming what can be the Ka

Answer: Acid (Ka is bigger than Kb), Kb = 10 -14 / step 3.4 * 10 -step 3 = 2.94 * 10 -a dozen

Allow the Ka and you will share with perhaps the agents are an acidic or foot if it possess good Kb of 5.6 * 10 -7 .

Answer: Feet (Kb are bigger than Ka), Ka = 10 -14 / 5.six * ten -seven = step 1.78 * ten -8