IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Sciences => Topic started by: yasser37 on May 25, 2010, 08:53:57 am

Title: Chemistry KMnO4
Post by: yasser37 on May 25, 2010, 08:53:57 am
hi guys

What's the difference between using hot and cold KMnO4

for example in June 06 Q.4 Part f

thanks
Title: Re: Chemistry KMnO4
Post by: unknown 101 on May 25, 2010, 03:04:03 pm
Quote from: yasser37 on May 25, 2010, 08:53:57 am
hi guys

What's the difference between using hot and cold KMnO4

for example in June 06 Q.4 Part f

thanks


hope this helped.. :)

if u still cant answer the question, tell me and i will help you ;)
Title: Re: Chemistry KMnO4
Post by: yasser37 on May 25, 2010, 03:14:17 pm
oh now I get it

thanks m8


will come up with more questions soon
hope to find you then


I finally got this
Title: Re: Chemistry KMnO4
Post by: unknown 101 on May 25, 2010, 03:20:02 pm
Quote from: yasser37 on May 25, 2010, 03:14:17 pm
oh now I get it

thanks m8


will come up with more questions soon
hope to find you then


I finally got this

ur welcome :)

dont worry ill be here ;)
Title: Re: Chemistry KMnO4
Post by: aldehyde1612 on May 26, 2010, 03:11:18 pm
On that photocopy sheet... where u said with hot KMno4 will give a carboxylic acid or ketone....
do u mean that the CH2 will be removed and replaced by O (i know theres bond breaking/formings etc.. but for visual aid) and the double bond on the CH2 will also be replaced by a O... giving two carboxylic acids ??
... or just the double becomes a single and then forms a carboxylic and ketone...???
Title: Re: Chemistry KMnO4
Post by: unknown 101 on May 26, 2010, 04:00:18 pm
Quote from: aldehyde1612 on May 26, 2010, 03:11:18 pm
On that photocopy sheet... where u said with hot KMno4 will give a carboxylic acid or ketone....
do u mean that the CH2 will be removed and replaced by O (i know theres bond breaking/formings etc.. but for visual aid) and the double bond on the CH2 will also be replaced by a O... giving two carboxylic acids ??
... or just the double becomes a single and then forms a carboxylic and ketone...???

if u still dont get it, just tell me i will try to explain it better if i can
sorry if i have bad handwriting  ;D

hope it helped ;)
Title: Re: Chemistry KMnO4
Post by: aldehyde1612 on May 26, 2010, 06:11:50 pm
oooh. right.. that makes sense.
thanks. !!!

ur writing looks like my bros... so im used to it. ;D
Title: Re: Chemistry KMnO4
Post by: Phosu on May 27, 2010, 02:36:18 pm
Quote from: unknown 101 on May 26, 2010, 04:00:18 pm
if u still dont get it, just tell me i will try to explain it better if i can
sorry if i have bad handwriting  ;D

hope it helped ;)

can u plz tell bout aldehyde
Title: Re: Chemistry KMnO4
Post by: Ykov on May 27, 2010, 02:56:02 pm
What's wrong with aldehyde? If it's about oxidation, yes, it can be oxidised to carboxylic acid, Cr2O72-/H+

It can also undergo reduction using 3 methods, either LiAlH4, which is kept under dry ether because it is explosive, or you can reflux it with NaBH4 or you can react it with hydrogen and a Ni/Palladium catalyst. The product is usually primary alcohols

Anything else you want to know?