GT for Chemistry paper 22 AS.

[robotic94]

Let's not worry too much about that okay? There's still P4 ahead

oh you are giving AS and A2 both?

 

[Pals_1010]

oh you are giving AS and A2 both?

Yes

 

[aom]

Alkenes undergo electrophilic addition

thats with halogens my friend

 

[Pals_1010]

thats with halogens my friend

Halogenoalkanes undergo Nucleophilic Substitution

 

[aom]

Halogenoalkanes undergo Nucleophilic Substitution

elecrophillic addition is only when Cl2 or Br2 reacts with alkene.......... end of discussion

 

[Pals_1010]

elecrophillic addition is only when Cl2 or Br2 reacts with alkene.......... end of discussion

http://www.docbrown.info/page06/OrgMechs1b.htm#catalysed

With steam also.... My job here is done

 

[ishan123]

In the first question the pH of Al chloride was in the range 1-3
and the reaction was hydrolysis.

damn.. thnx nbtw, do you know aboutany of the other doubts ive highlighted?
thnx again

 

[aom]

http://www.docbrown.info/page06/OrgMechs1b.htm#catalysed

With steam also.... My job here is done

good that u posted this the OH is for the acidic solution (catlysed) but the halogen (Br2 or Cl2) is in the aqueos media.... its just above the one u posted

 

[aom]

good that u posted this the OH is for the acidic solution (catlysed) but the halogen (Br2 or Cl2) is in the aqueos media.... its just above the one u posted

and another thing its not in the syllabus the one ur taking about

 

[Pals_1010]

and another thing its not in the syllabus the one ur taking about

Yes, it is in the syllabus: The reaction with steam catalysed by phosphoric acid to produce alcohols. Am not denying the fact that halogens react by this mechanism. In fact, both steam and halogens react with alkenes by electrophilic addition. That's what I am saying

 

[00tanveer]

2H2 + O2 --> 2H2O Cheers

 

[00tanveer]

ANY addtion reactions of alkenes are electrophilic, dude.

 

[gary221]

ANY addtion reactions of alkenes are electrophilic, dude.

Yeah thts right!!
@ Alkene + H2O = Alcohol

 

[Saad Sarfraz]

327 is a high temperature for this reaction as it was exothermic so while the reaction takes place it will also generate heat thus its a pretty good temp..........

One more thing about enthalpy change. How was it 129, + or -. mine was coming 400 something
I asked some candidate( s ) who got 129 kJper mol , but they took also the enthalpy change of combustion of H2( g ) while making the cycle ( Hess's law ). I thought data of enthalpy change of combustion of H2( g ) was a trick! Because there's no enthalpy change from H2 ( g ) to H2 ( g )!
Anyone else got this??

Lool there is no enthalapy change of formation on an element like H2 but there is definitly and enthalpy change of combustion and u had to use it!

 

[Saad Sarfraz]

guys what are your thoughts on this for the aluminium burning in chlorine question i wrote the equation as 2AL(s) + 3Cl2(g) ---> Al2Cl6(g) is the examiner gona allow this?

 

[gary221]

guys what are your thoughts on this for the aluminium burning in chlorine question i wrote the equation as 2AL(s) + 3Cl2(g) ---> Al2Cl6(g) is the examiner gona allow this?

I actually think this IS the right ans...as AlCl3 is nt stable...

 

[leosco1995]

I think both would probably be acceptable, no?

 

[gary221]

Maybe...bt thts just wht i think

 

[Saad Sarfraz]

I actually think this IS the right ans...as AlCl3 is nt stable...

Man that's was the only reason i wrote it and since everyone and yes everyone else in my school about 500 students wrote ALCL3 so it made me doubt mine. One or 2 quite able students said that for a question like this the examiner allows both answers so hoping inshAllah that happens

 

[iceman]

in the last question the two functional groups present were alcoholl and ketone right?.....but instead of alcohol i accidently wrote aldehyde...( silly mistake ) ....my question is that will i get error carried forward in the later parts of this question....considering the fact that penalization for same mistake again and again would be unfair... quick reply plzzz