is this right?--ionization - (Aug/11/2007 )

hi there

can someone please see if i have the right answer...hv a test tomorrow and just wanna make sure im doing it right..

its assumed that 2mL of 1M NaOH added to 6mL of a diluted solution of tyrosine fully ionises the side chain Tyr-O^-, and that 1M HCl gives a fully protonated side chain Tyr-OH. the absorbance at 296nm of the fully ionised form=0.712 and the absorbance for the protonated form was -0.038. after addition of 2mL of 180mL of NaOH the absorbance was 0.593. the resulting % ionization is?

and so i did...0.593/0.712*100=83.3%

now to me this seems right but its a multi choice question and my answer isn't there..

the options present are
a-84.1%
b-79.1%
c-100%
d-80%
e-50%

maybe a is the right answer? sumone please help

Thanks in advance
b_06er

hi there

can someone please see if i have the right answer...hv a test tomorrow and just wanna make sure im doing it right..

its assumed that 2mL of 1M NaOH added to 6mL of a diluted solution of tyrosine fully ionises the side chain Tyr-O^-, and that 1M HCl gives a fully protonated side chain Tyr-OH. the absorbance at 296nm of the fully ionised form=0.712 and the absorbance for the protonated form was -0.038. after addition of 2mL of 180mL of NaOH the absorbance was 0.593. the resulting % ionization is?

and so i did...0.593/0.712*100=83.3%

now to me this seems right but its a multi choice question and my answer isn't there..

the options present are
a-84.1%
b-79.1%
c-100%
d-80%
e-50%

maybe a is the right answer? sumone please help

Thanks in advance
b_06er