# Chem – College: Dating Between Acid and you may Foot Equilirium Constants (Ka and you will Kb)

Chem – College: Dating Between Acid and you may Foot Equilirium Constants (Ka and you will Kb)

When you are given multiple Ka or Kb values (like Ka step one , Ka dos , Ka step step step step 3 ), 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?

## In the event 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 you to Ka and you can Kb was pertaining to one to another inside the an algorithm. So it formula allows you to convert out-of Ka so you can Kb and vise versa. Brand new algorithm is actually shown below .

The great thing about which algorithm could it possibly be in addition to allows you to help you assume whether things are an acid otherwise a base . The way to contour if things are an acid or base by the Ka otherwise Kb worthy of is to try to evaluate they to the harmony constant for drinking water such as the newest picture lower than.

When your Ka transforms planning to end up being a bigger matter than brand new Kb then the chemicals might be an acid.

Should your Kb turns going to getting a larger matter than simply the fresh new Ka then the toxins might possibly be a bottom.

Give the Kb and you will give perhaps the agents is an acidic otherwise ft if this have a great Ka regarding dos.cuatro * 10 -six .

Answer: Acid (Ka are bigger than Kb), Kb = 10 -fourteen / 2.4 * ten -six = cuatro.17 * 10 -nine

Provide the Ka and give if the toxins is actually an acid or feet if it has an effective Kb regarding step three.5 * 10 -4 .

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

Supply the Kb and tell whether the chemical is actually an acidic otherwise foot when it has actually a great Ka guyspy off 4.step three * 10 -nine .

Answer: Foot (Kb is bigger than Ka), Kb = ten -fourteen / cuatro.3 * 10 -nine = 2.thirty two * 10 -six

Give the Ka and give if the chemical substances is actually an acid otherwise feet when it keeps an effective Kb out of 8.9 * ten -eleven .

Answer: Acid (Ka are bigger than Kb), Ka = 10 -fourteen / 8.9 * ten -11 = 1.twelve * 10 -4

Provide the Kb and tell whether or not the chemicals was an acidic or ft when it features an excellent Ka out-of eight.2 * 10 -nine .

Answer: Base (Kb was bigger than Ka), Kb = 10 -14 / 7.dos * ten -nine = step 1.38 * ten -six

Give the Ka and you will tell whether or not the chemical substances try an acidic otherwise feet whether or not it provides a good Kb from cuatro.dos * ten -twelve .

Answer: Acid (Ka are bigger than Kb), Ka = 10 -fourteen / cuatro.2 * ten -11 = dos.38 * ten -4

Provide the Kb and you can tell if the toxins is an acid otherwise legs whether or not it features an excellent Ka out of 3.4 * 10 -step three .

## Then what would function as the Ka

Answer: Acid (Ka are larger than Kb), Kb = ten -14 / 3.cuatro * ten -3 = dos.94 * ten -12

Allow the Ka and you can give whether or not the toxins are an acid or ft if this possess a good Kb of 5.6 * ten -seven .

Answer: Base (Kb was bigger than Ka), Ka = 10 -14 / 5.6 * 10 -7 = step 1.78 * ten -8