Chemistry: Post your doubts here!

[daredevil]

well Na reacts with alcohol phenol and carboxylic acid right so given this fact there are 6 hydrogen available to be replaced with Na metal 6 hydrogen atoms. 2 atoms in one molecule so 3 moles .
for (a) alcohols dont react with NaOH so 3 will react
for (b) again 2 OH of phenols and 1 OH of carboxylic acid will react but this time there would also be base hydrolysis so total 4 moles of NaOh required

okaayy i got the one with H but not the a and b parts..
if alcohols dont react then with which parts of the compound will 3 NaOH react?
same with the b part....

ummm are u saying that the phenols and carboxylic acid will react in a and b parts but alcohols won't ?

 

[daredevil]

daredevil 6Astarstudent can anyone help me understand that highlighted text in 3rd file from right well i think it contradicts with the data booklet in 4th file View attachment 38936 View attachment 38937 View attachment 38938 View attachment 38939

actually i was going to ask u the same question too...


A star syed1995 MustafaMotani u guys have any idea how to do this?? it's Q7 of May/June 2013 Paper 42

 

[A star]

actually i was going to ask u the same question too...


A star syed1995 MustafaMotani u guys have any idea how to do this?? it's Q7 of May/June 2013 Paper 42

am on it wait snowbrood

 

[sitooon]

3 mol of H2 are produced because Na will react with the 2 OH on the phenol and the 3 OH on the other ring and also with the OH of the acid group..so u have 6mol of H -----> 3 mol of H2

a) in the cold - 3 mol of NaOH (reacts with the 2 OH on the phenol and the acid group )
b) when heated - 4 mol of NaOH (breaks the ester bond in addition to reacting with the ones above)

daredevil

 

[A star]

actually i was going to ask u the same question too...


A star syed1995 MustafaMotani u guys have any idea how to do this?? it's Q7 of May/June 2013 Paper 42

ok guys here is my train of thought hope you follow(p.s I may be wrong so correct me if I am)
the compound has a total of 7 hydrogens and 7 carbons.
Now the peak at7.something confirms that it has a benzene ring. Now there must also be an OH that reacts with the Na metal but if we forma phenol with a chlorine attached it would leave a carbn short in our structure. so there must be an alcohol which is left which reacts with sodium metal as carboxylic acid would once again not fullfill the structure. now by attaching a chlorine and a methyl alcohol we remove 2 hydrogen and add three satisfying the no of Cs,Cls,Hs

 

[snowbrood]

okaayy i got the one with H but not the a and b parts..
if alcohols dont react then with which parts of the compound will 3 NaOH react?
same with the b part....

ummm are u saying that the phenols and carboxylic acid will react in a and b parts but alcohols won't ?

yea ofcourse thats the way it is

 

[chocolate_girl]

I have some problem in organic chemistry can someone please elaborate these syllabus content for me

1)describe the formation of carboxylic acids from nitriles

2)describe the reactions of carboxylic acids in the formation of acyl chloride

3)describe the formation of amides from the reaction between RNH2 and R'COCl

4)describe amide hydrolysis on treatment with aqueous alkali or acid

Thanks in advance

 

[daredevil]

Suggest an explanation for the lack of reactivity of the nitrogen molecule, N2. [1]

 

[Namehere]

Suggest an explanation for the lack of reactivity of the nitrogen molecule, N2. [1]

Nitrogen triple bond is very strong.

 

[snowbrood]

ok guys here is my train of thought hope you follow(p.s I may be wrong so correct me if I am)
the compound has a total of 7 hydrogens and 7 carbons.
Now the peak at7.something confirms that it has a benzene ring. Now there must also be an OH that reacts with the Na metal but if we forma phenol with a chlorine attached it would leave a carbn short in our structure. so there must be an alcohol which is left which reacts with sodium metal as carboxylic acid would once again not fullfill the structure. now by attaching a chlorine and a methyl alcohol we remove 2 hydrogen and add three satisfying the no of Cs,Cls,Hs

bro this is not what i asked i know how to solve this type of question but what confuses me is why did the examiner say that the chemical shift value of secondary alkane is close to 4 when it should be 1.3 why is this the case was examiner drunk . in one paper he wrote (200/1.1) when he should have written 100/1.1 for finding the number of c atoms

 

[chocolate_girl]

Is this thread for as level students aswell?

 

[chocolate_girl]

What is the bond angle and structure of trigonal bipyramid e.g PF5

 

[Namehere]

What is the bond angle and structure of trigonal bipyramid e.g PF5

It is for AS students too.

It has bond angles of 90 and 120 degrees.

 

[chocolate_girl]

describe covalent bonding in terms of orbital overlap, giving σ and π bonds, including the concept of hybridisation to form sp, sp2 and sp3 orbitals
What is the concept of hybridisation?

 

[chocolate_girl]

It is for AS students too.

It has bond angles of 90 and 120 degrees.

Thankyou so soooo muchh would u please see my post above nd try to ans my queries? I will b greatful

 

[chocolate_girl]

It is for AS students too.

It has bond angles of 90 and 120 degrees.

Can u also make the image of the structure in my mind nd that does it have both 90 or 120 angle or only 1?

 

[chocolate_girl]

1. understand, in simple terms, the concept of electronegativity
   and apply it to explain the properties of molecules such as bond polarity (3h), the dipole moments of molecules (3j), the behaviour of oxides with water (3.1j) and the acidities of chlorine-substituted ethanoic acids (10.6c)
   
   Please explain me the last chlorine substituted ethanoic acid part aswell

 

[Namehere]

The answer to your questions can be easily found in your book and by researching on the internet. I would love to help everyone, but unfortunately I do not have the time to please everyone.

 

[chocolate_girl]

The answer to your questions can be easily found in your book and by researching on the internet. I would love to help everyone, but unfortunately I do not have the time to please everyone.

Its okay mayb somebody else will

 

[daredevil]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_42.pdf

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_42.pdf

Q4. if we do not branch C as given in the marking scheme ... see the snapshot. the elements are full and the alkene and carboxylic acid groups are there...
what am i missing?? or does it not make a difference if it is branched or not?