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Yield % Problem

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Hello,
I need to calculate the yield % of [(Ph)3PH]2[CoCl4]

The actual yield is 2.715g
My issue is with the theoretical yield, here is how I did it:

I'm following this reaction that was given in the explanations of my homework; (C6H5)3P + HCl => (C6H5)3PH+ + Cl-

Molar mass of (C6H5)3P: 262.29 g/mol
Molar mass of (C6H5)3PH+: 263.30 g/mol
Mass of Triphenylphosphine measured: 1.062 g

n(triphenylphosphine)=m(triphenylphosphine)/M(triphenylphosphine) =1.062g/(262.29 g/mol)=4.049×10-3 mol

Molar mass of [(Ph)3PH]2[CoCl4] : 727.33 g/mol
Since there are 2 molecules of (Ph)3PH in the [(Ph)3PH]2[CoCl4], the n(triphenylphosphine) needs to be divided by  2.

n([(Ph)3PH]2[CoCl4])=n(triphenylphosphine)/2=2.025×10-3 mol

m[(Ph)3PH]2[CoCl4] =n[(Ph)3PH]2[CoCl4] ×M[(Ph)3PH]2[CoCl4]

m[(Ph)3PH]2[CoCl4] =(2.025x10-3 mol)×(727.33 g⁄mol)
m[(Ph)3PH]2[CoCl4] =1.479 g = Theoretical yield

You see, my theoretical yield is smaller than my actual yield.
If someone sees my mistake, please let me know.

Thank you,
MV101

It would help the clarity of your question if you defined n, m, and M clearly and unambiguously.

  • Author

n is the # of moles.

m is the mass of the measured samples

M is the Molar mass of the comound.

So far, I have not found an error.  I did see one thing that bothered me a bit, and it could be a clue.  It is difficult to see how the protonated form of a phosphine could be a ligand to the metal ion.  The unprotonated form would be fine.

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