[sapta]

I am writing a line from my book-

"K₂Cr₂O₇-H₂SO₄  i.e. chromic acid-H₂SO₄ mixture is known as jone's reagent.Unlike acidified K₂Cr₂O₇,it does not affect a double bond."

Does it mean that conc. H2SO4 is used in the former reagent?No other book makes this distinction.So, is there really any difference?plz also inform me about their specific applications.

THANKING YOU IN ADVANCE.

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I AM REALLY LEARNING FROM THIS SITE.

[AWK]

Jones reagent is diluted a few times by water or acetonebefore using

[dexangeles]

I am writing a line from my book-

"K₂Cr₂O₇-H₂SO₄  i.e. chromic acid-H₂SO₄ mixture is known as jone's reagent.Unlike acidified K₂Cr₂O₇,it does not affect a double bond."

Does it mean that conc. H2SO4 is used in the former reagent?No other book makes this distinction.So, is there really any difference?plz also inform me about their specific applications.

THANKING YOU IN ADVANCE.

--------------------------------------------------------------

I AM REALLY LEARNING FROM THIS SITE.

I am learning from this site too let's all learn!!!

hint:
1. what chromates or dichromates do? Is it the oxidizing agent?  Or is it the compound formed after acidifying?  Also ask yourself this, what does water do to salts? Remember, K₂Cr₂O₇

[sapta]

hmmmm :hrmm:,as far as i know,K2Cr2O7(or the Cr2O7^-2 ion) is the oxidising agent.But,it also evolves nascent oxygen(with H2O and dil. H2SO4). So that may be the real oxidising agent.

But i still don't get it.i mean what's the difference between Jone's reagent and acidified K2Cr2O7? they should be the same thing.

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sorry for the delay in replying.

[ksr985]

JONES REAGENT:

this is chromic acid+sulphuric acid in water...that is Cr[2]O[3] + H[2]SO[4]
When secondary alcohols are dissolved in acetone, titration with this reagentyields ketones in high yield, without disturbing any double or triple bonds, and without epimerizing adjacent chiral carbon centers. This reagent also converts allylic alcohols to aldehydes.

[sven222]

According to my lab notes, Jones' Reagent is a mixture of,

"26.7g Chromium Trioxide, 23ml conc. sulfuric acid, made up to 100ml with water"

Nice dark red solution, accidently spilt a drop on my wrist though. That wasn't pleasent.