Chemistry: Post your doubts here!

[Krypton36]

Anybody got the 9701 March 2018 Paper 42??

 

[Fardeen3342]

]

View attachment 63528
March 2017 Q6f(iii)

View attachment 63529
March 2017 Q7e(i)

Help me out any Chem Expert
anastasia grey113

its carbon environments so there are 3 different environments in the side chain and 4 different in the benzene ring itself

 

[Fardeen3342]

i cant understand please help

 

[anastasia grey113]

i cant understand please help

is it Nitrogen and sulfur?
for that u need to remember the test for sulfate ion
BaSO4 is insoluble unlike MgSO4

 

[Fardeen3342]

is it Nitrogen and sulfur?
for that u need to remember the test for sulfate ion
BaSO4 is insoluble unlike MgSO4

i got that part its the nitrogen and cl part how is overall charge of clo3 -1? m16 42 for your reference

 

[anastasia grey113]

i got that part its the nitrogen and cl part how is overall charge of clo3 -1? m16 42 for your reference

well it could be cuz do u remember the react ion of chlorine with hot NaOH to make NaClO3?
in it Cl has a charge of +5.
that's how its -1.

 

[anastasia grey113]

i got that part its the nitrogen and cl part how is overall charge of clo3 -1? m16 42 for your reference

but they said 'adjacent'groups
then how come its Cl and N?
theyr not from adjacent groups

 

[anastasia grey113]

i got that part its the nitrogen and cl part how is overall charge of clo3 -1? m16 42 for your reference

well i checked the mark scheme and it says sulfur and nitrogen

 

[Bilal hassan]

Hey guys, hope you guys are studying well for paper 4. I am wondering about this question, why when excess bromine is added, it only attaches to the phenyl group and doesn't add to the double bond by electrophilic addition. Is it a rule? Thanks and good luck

 

[Fardeen3342]

Hey guys, hope you guys are studying well for paper 4. I am wondering about this question, why when excess bromine is added, it only attaches to the phenyl group and doesn't add to the double bond by electrophilic addition. Is it a rule? Thanks and good luckView attachment 63538

The state of br2 should be liquid i think and not aq

 

[anastasia grey113]

Hey guys, hope you guys are studying well for paper 4. I am wondering about this question, why when excess bromine is added, it only attaches to the phenyl group and doesn't add to the double bond by electrophilic addition. Is it a rule? Thanks and good luckView attachment 63538

lol i dint quite get this either
my teacher also dint get the concept behind this
but he said that if there are two reactions ans theyre asking for one, the one with phenol should be considered

 

[anastasia grey113]

The state of br2 should be liquid i think and not aq

lol idky its stated like this here
but the bromine that is used is always dissolved in water
becuz if thats not done, bromine itself is a volatile liquid and would easily evaporate before all of the ethene reacts

 

[Zaki ali asghar]

https://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s17_qp_42.pdf for Q3Biii why do we divide the answer in ii by 3? pls explain

 

[anastasia grey113]

https://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s17_qp_42.pdf for Q3Biii why do we divide the answer in ii by 3? pls explain

Because in the previous part u calculated no. of moles of NaOH.
Now consider both the equations
2NaOH + SO2----> Na2SO3 +H2O
NaOH + HCl ------> NaCl + H2O
so u see that three moles of NaOH r required to react with one mole of SO2 and 1 of HCl.
So to produce 1 mole of HCl and of SO2 the RCOOH should be 1/3 of the NaOH.

 

[Zaki ali asghar]

https://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s17_qp_42.pdf for Q7 what is the diff b/w test 1 and 2? aren't the both to test for chloride ions?

 

[Zaki ali asghar]

can someone tell about the solubility of amides and amine in HCL? and with cold/hot hcl?

 

[Holmes]

]

its carbon environments so there are 3 different environments in the side chain and 4 different in the benzene ring itself

WHAT????????????????????????

 

[Holmes]

lol i dint quite get this either
my teacher also dint get the concept behind this
but he said that if there are two reactions ans theyre asking for one, the one with phenol should be considered

too vague

 

[Holmes]

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-876#post-996155

anastasia grey113

 

[anastasia grey113]

https://www.xtremepapers.com/commun...st-your-doubts-here.9859/page-876#post-996155

anastasia grey113

The ones I've circled in red are all having different chemcal environments...these are 5 carbons
The two in blue have the same env. as they are both next to the adjacent C atom in benzene next to the side chain so we will consider this 1 env.
Same goes for both in green...they are BOTH next to the Carbon side chain linked to benzene so both have same env. so v will consider this one env. too
so 1 + 1+ 5 = 7 different env.

Nickel will have cis trans isomers because it has two pairs of different kinds of ligands. Just draw two planar structures.
Also since Ni is not bonded to a bidentate or 4 different ligands, there should be no optical isomerism here.