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Organic Chemistry

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12 Feb 2009 20:09:22 IST

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342

UNUSUAL Q--PLZZZZZ ANS-RATES ASSURED

None

CALCULATE ISOELECTRIC POINT OF LYSINE HAVING pK_a1=2.18 ,pK_a2=8.95 ,pK_a3=10.53

STRUCTR OF LYSINE IS HOOC-CHNH₃⁺-(CH₂)₃-CH₂NH₃IN STRONG ACIDIC MEDIUM.............

(A)2.18

(B)9.74

(D) 5.57

PLZZZZZZZZZZZZ EXPLN THE CONCEPT.........

M WAITING

PLZ ANS IMMDTLY...........

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Comments (5)

Sai Karthik

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12 Feb 2009 20:45:41 IST

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at isoelectric point is where net charge on mole cule is 0 so it does not migrate to any end of electrode. when u draw the sructures at the 3 phs given between pka2 and pka3 we get a sructure where net charge is zero so isoelectric point is 8.95+10.53/2 = 9.74 i think plz rate PS : srry i couldnt post the structure

JPS

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12 Feb 2009 21:01:31 IST

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isoelectric point is the point at which net charge on the molecule is 0. so, ans should be 8.95+10.53/2 = 9.74.........RATE IF CORRECT.

abhishek

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14 Feb 2009 19:15:54 IST

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yes this is the correct ans .The ques appeared in the FIITJEE part test 2,2009.

Yash: Save Tigers..!!

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14 Feb 2009 21:20:38 IST

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yep the correct answer is B !~

Madmax

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20 Feb 2009 19:21:24 IST

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This concept is often used in problems.......Just follow what Sai has explained....his explanation is straightforward and to the point!!Cheers!!

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