Chemistry: Post your doubts here!

[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.

 

[Fardeen3342]

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

Ahahahahah read this ^ she explained it well

 

[Fardeen3342]

But Ni is bonded to en. Isnt en(NH2CH2CH2NH2) a bidentate ligand?

if there were 3 en ligands you could have done optical but in this case its 2 different ligands 2 en's and one other ligand so its cis trans

 

[Holmes]

anastasia grey113 Thanks

 

[anastasia grey113]

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

Amines are soluble in both hot and cold as they ionise by accepting protons.
Amides are not soluble in cold.
However, in hot acid, they hydrolyse to form an acid and an amine so yh u can say that the products formed by amide are soluble

 

[anastasia grey113]

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?

the AgNO3 is for all halides and is usually used to find if halogenoalkane is chloro bromo or iodo
white forms quickly for chlorides, cream white forms slowly with Br and yellow forms with I.
While test 2 is only for chlorides
however, since only chlorine is mentioned in the molecular formula, i dont think there was any point of including two tests :/

 

[Zaki ali asghar]

View attachment 63544
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.

hey, what's the diff between the blue and green ones? :/

 

[anastasia grey113]

hey, what's the diff between the blue and green ones? :/

one is directly bonded to the carbon with the side chain
while one is bonded to the carbon thaz next to the carbon with the side chain

 

[haithsoul]

the AgNO3 is for all halides and is usually used to find if halogenoalkane is chloro bromo or iodo
white forms quickly for chlorides, cream white forms slowly with Br and yellow forms with I.
While test 2 is only for chlorides
however, since only chlorine is mentioned in the molecular formula, i dont think there was any point of including two tests :/

there is a difference, in the question for w it says for immediately thus its acyl chloride, for y its very slow so its chloro alkane. Since acyl cholrides are far more reactive

 

[Zaki ali asghar]

https://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s17_qp_43.pdf here in 2ci while calculating the conc of OH- at the end why do we use the total volume of 50cm^3 ? wouldn't the volume be used up during titration?

 

[haithsoul]

https://papers.gceguide.com/A Levels/Chemistry (9701)/9701_s17_qp_43.pdf here in 2ci while calculating the conc of OH- at the end why do we use the total volume of 50cm^3 ? wouldn't the volume be used up during titration?

you are adding 30cm3 to 20 so 50 in the flask at the end?

 

[Minsa Fatima]

How do we come to know where to place the Cl and NH3? Cant there be any other arrangement apart from these?

 

[harishassan1399]

There is no equation in the data booklet matching the one given in the mark scheme. How is this answer obtained?

 

[Mts.99]

There is no equation in the data booklet matching the one given in the mark scheme. How is this answer obtained?

I think since theres excess of Fe ions, they ll first oxidize vanadium metal to V2+, then V2+ to V 3+, then V3+ to VO2+. Since all of them have E less than +0.77

 

[harishassan1399]

I think since theres excess of Fe ions, they ll first oxidize vanadium metal to V2+, then V2+ to V 3+, then V3+ to VO2+. Since all of them have E less than +0.77

Thanks