CHEM P42 GT and paper discussion

[A star]

in reduction of PbCl2 i wrote
Pbcl2 + Fe2+ = Pbcl + Fe3+
is this correct ??

nope the answer should be Pb metal no Pb1+ no group four forms 1+ ions. you could use a reducing agent like KI

 

[A star]

is question ma 2 baar functional groups ka pucha tha??i forgot

nope yar first he asked which group gave the iodoform test. then asked which of the ISOMERS gave the positive test. Allah ka shukar hae i will get 96-98 or even 99 due to ecf in the explaination in the chem paper and even with a gt in the 68 you just ned to get 90+ to be considered full so cheers

 

[saadgujjar]

nope yar first he asked which group gave the iodoform test. then asked which of the ISOMERS gave the positive test. Allah ka shukar hae i will get 96-98 or even 99 due to ecf in the explaination in the chem paper and even with a gt in the 68 you just ned to get 90+ to be considered full so cheers

I may get 91..92

 

[A star]

I may get 91..92

hope you didnt mind the argument actually i didnt even know about it till you tild me :/

 

[saadgujjar]

hope you didnt mind the argument actually i didnt even know about it till you tild me :/

argument about E value?

 

[rockpapers]

What do you guys think will the A* boundary be??? Like 200-205 or more or less???

 

[saadgujjar]

a star plz explain how did u do pbcl2 question

 

[A star]

a star plz explain how did u do pbcl2 question

well idk i wrote
Pbcl2 + 2KI --> Pb(s) +I2(aq) + KI Pb2+ is reduced to Pb

 

[saadgujjar]

well idk i wrote
Pbcl2 + 2KI --> Pb(s) +I2(aq) + KI Pb2+ is reduced to Pb

what did u write in above question pbcl2 and sncl2 behavior towards oxidizing agent ?what E values to quote

 

[A star]

all of them from 0 to 2 and from 2 to 4. then compare them

 

[saadgujjar]

all of them from 0 to 2 and from 2 to 4. then compare them

I have only done 2 papers for p5....are any solved papers available

 

[A star]

I have only done 2 papers for p5....are any solved papers available

my coachng sir gave them too me i have like 2007 onwards all of them they are so easy i am gona ace them (Y)

 

[TANJIAHOU]

The argument about the E° value is simple.

• The more negative the E° value, the further the equilibrium lies to the left - the more readily the element loses electrons and forms ions.
  

 

[goodluckayesha]

my coachng sir gave them too me i have like 2007 onwards all of them they are so easy i am gona ace them (Y)

can u plz post them or smthn like tht? it wud be really helpful

The argument about the E° value is simple.

• The more negative the E° value, the further the equilibrium lies to the left - the more readily the element loses electrons and forms ions.

i wish i had known this earlier......

 

[A*(a*)]

CAN anyone tell me the answer with refrence to the 5 mark transition elements qs?!
as nh3 was added to cucl4. 3 colour changes and ions responsible for them?

 

[rana14197]

Ppl what was the answer for properties of separation by paper chromatography and electrophoresis question ??

 

[rana14197]

And walhat was the best indicator ???

 

[rana14197]

Do u think the A* threshold will be higher than 205 ???

 

[A star]

CAN anyone tell me the answer with refrence to the 5 mark transition elements qs?!
as nh3 was added to cucl4. 3 colour changes and ions responsible for them?

when Nh3 was added it acted like a base neutalising the Cl- ions in the solution so the green colour faded and a light blue solution of Cu(h2o)6 was formed. then adding more NH3 precipitated it out Cu(OH)2 and then the Cu(NH3)4(H2O)2 complex forming dark plue solution

 

[A star]

Ppl what was the answer for properties of separation by paper chromatography and electrophoresis question ??

net charge/mass and absorption of different amino acids