What is the pH of 0.5M FeCl3?

Updated: 9/15/2023
User Avatar

Wiki User

12y ago

Best Answer

I am assuming that this FeCl3 is going to be aqueous, as it usually is. Therefore, Fe+3 forms complexes in water in the following manner:

B FeCl3(aq) +6H2O → [Fe(H2O)6]3+

Now, because the Fe has a positive charge, it will pull the negative electron cloud towards itself, making the bond holding the H on the OH weaker, which leads to an easier release of protons (H+). Therefore,

[Fe(H2O)6]3+ → [Fe(H2O)5]+2 + H+

As you can see, Fe is in the "net reaction" acting as an acid, as it makes the H2O's bound to it release H+ ions into the water. Therefore, FeCl3 is assigned a Ka value, which = 2.0 x 10-3.

Now, we need to set up our table:

FeCl3 →




Initial concentration

0.5 M

0.0 M

0.0 M


(-) x



Final Concentration




So, we can set up our equilibrium constant expression:

Ka= [H+][ [Fe(H2O)5]+2]/[[Fe(H2O)6]3+]

we know Ka therefore:

2.0 x 10-3= x2/0.5-x

Solve for x, must use quadratic:

0.001-2.0 x 10-3x-x2=0

Solving the quadratic gives us:

x= -0.032639, 0.030639

The negative result is unphysical, because we cannot have a negative concentration, therefore, x= 0.030639, which from our graph tells us that the concentration of H+ = 0.030639M, so to find the pH:

-log( 0.030639)= pH = 1.51, so therefore, the pH of 0.5 M FeCl3 is 1.51.

Hope that helps, don't know if you needed to know all the details.

Praise God!


User Avatar

Wiki User

12y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: What is the pH of 0.5M FeCl3?
Write your answer...
Still have questions?
magnify glass
Related questions

How do you prepare 05M glutaraldehyde?

how to prepare .05M glutaraldhyde solution molecular weight is 100.12

How long is flight from Manchester to johanasburg?

34h 05m

How do you find 1.1 grams of feci3 In moles?

FeCl3 ? 1.1 grams FeCl3 (1 mole FeCl3/162.2 grams) = 0.0068 moles of FeCl3 ------------------------------------

What is the concentration of FeCl3 in a solution prepared by dissolving 40.0 g of FeCl3 in enough water to make 275 mL of solution?

Look up or calculate the molecular weight/molar mass of FeCl3. Then... 40.0 g FeCl3/MW FeCl3/0.275 L = M (concentration of FeCl3 in solution)

What is the nomenclature for FeCl3?

FeCl3 has the name iron III chloride

What results when you have fecl3 and kscn and agno3?

FeCl3 +KSCN + AgNO3

What is an ionic equation for FeCl3 plus H2SO4?

FeCl3 + H2O4-2 +Zn

Is FeCl3 soluble in water?

No, pure FeCl3 is not aqueous.

How neutral fecl3 solution prepare?

Take 1 ml FeCl3 solution. add ammonia solution drop wise till brown precipitate just form. Now again add FeCl3 solution till brown precipitate just dissolve. This is your Neutral FeCl3 solution.

Salicyclic acid gives a positive test with FeCl3?

why does salicylic acid give a positive test with FeCl3

How many milliliters of 0.200 M FeCl3 are needed to react with an excess of Na2S to produce 2.75 g of Fe2S3 if the percent yield for the reaction is 65.0 percent?

.2M x V FeCl3=moles FeCl3 x 1mole Fe2S3/2mole FeCl3=moles of Fe2S3 x mm of Fe2S3/1 mole Fe2S3= g Fe2S3 x .65% yield. 2.75g Fe2S3/ .65= 4.23g Fe2S3/ 207.91= .02035 x 2mole FeCl3=.0407 moles FeCl3/ .2M FeCl3= .2035 L x 1000= 203.5 ml

What would be seen if you analyze salicylic acid in FeCl3 test?

what would be seen if you analyzed salicylic acid in FeCl3?