Chemistry: Post your doubts here!

[BasilBassam]

Hello Guys can you please help me: when there is a phenol group on the ring and you add Br2 (Aq) substitution occurs on 2,4,6 carbons. Many questions came where there are two phenol groups on the ring how will I know on which position bromine is added?
example is added

 

[Xylferion]

Hello Guys can you please help me: when there is a phenol group on the ring and you add Br2 (Aq) substitution occurs on 2,4,6 carbons. Many questions came where there are two phenol groups on the ring how will I know on which position bromine is added?
example is addedView attachment 53048

I believe that the bromine atoms would attach themselves across the double bond. So I'd basically draw that same structure, without the double bond, and a Br atom attached to each carbon that was present in the double bond.

 

[Turki AbdulAziz]

When Magnesium burns (in Oxygen/Steam) It burns with a white flame. For the observation of the reaction, should I use this or should I say Magnesium glows?? Because books mention how Magnesium burns with a white flame while Marking scheme says Magnesium glows??

 

[qwertypoiu]

When Magnesium burns (in Oxygen/Steam) It burns with a white flame. For the observation of the reaction, should I use this or should I say Magnesium glows?? Because books mention how Magnesium burns with a white flame while Marking scheme says Magnesium glows??

Magnesium burns with a sparkling bright flame. Better not to mention any colour for it, we don't consider white a colour.
Sodium burns with golden yellow flame.
Sulfur burns with a pale blue flame.
I think phosphorus burns with yellow flame not sure though.

 

[Metanoia]

Hello Guys can you please help me: when there is a phenol group on the ring and you add Br2 (Aq) substitution occurs on 2,4,6 carbons. Many questions came where there are two phenol groups on the ring how will I know on which position bromine is added?
example is addedView attachment 53048

On the benzene ring, you can add 2 bromine atoms. Next to the OH groups.

 

[nehaoscar]

Anyone have a table of some sort or anything with all the reactions, reagents and conditions needed to be know for AS chemistry?
This would be for organic...
Please!

 

[The Sarcastic Retard]

On the benzene ring, you can add 2 bromine atoms. Next to the OH groups.

Anyone have a table of some sort or anything with all the reactions, reagents and conditions needed to be know for AS chemistry?
This would be for organic...
Please!

Best organic notes please?
mehria

 

[princess Anu]

for anything to be soluble in water, hydrogen bonds should exist between water and that substance right??
but in this ques MS says
hydrogen bonding is absent between Ethoxyethane molecules why?

 

[nehaoscar]

for anything to be soluble in water, hydrogen bonds should exist between water and that substance right??
but in this ques MS says
hydrogen bonding is absent between Ethoxyethane molecules why?

The hydrogens are attached to the carbons
For hydrogen bonding, you need a H attached to a F,O or N

 

[qwertypoiu]

for anything to be soluble in water, hydrogen bonds should exist between water and that substance right??
but in this ques MS says
hydrogen bonding is absent between Ethoxyethane molecules why?

Firstly, not all soluble substances have hydrogen bonding. Does NaCl have hydrogen bonds? No. (this dissolves because they are ions)
Secondly, in this question it says they form two layers. So ethoxyethane or whatever it is did NOT dissolve in water.
Thirdly, the molecule they gave cannot possibly have hydrogen bonds, it only has permanent dipole dipole interaction.

 

[princess Anu]

a

Firstly, not all soluble substances have hydrogen bonding. Does NaCl have hydrogen bonds? No. (this dissolves because they are ions)
Secondly, in this question it says they form two layers. So ethoxyethane or whatever it is did NOT dissolve in water.
Thirdly, the molecule they gave cannot possibly have hydrogen bonds, it only has permanent dipole dipole interaction.

I think you didn't understand my question

in ans to this I wrote because Hydrogen bonds donot form between ethoxyethane and H2O
but the Ms says
hydrogen bonds cannot form btween Ethoxyethane molecules :/

 

[Fahad Afzal]

http://maxpapers.com/syllabus-mater...chment/9701_oct-nov-2011-all-question-papers/

Q4 W ... Q5 b and c anyone?

 

[The Sarcastic Retard]

http://maxpapers.com/syllabus-mater...chment/9701_oct-nov-2011-all-question-papers/

Q4 W ... Q5 b and c anyone?

paper?
I have 5c paper 22 explanation of ma frn.
I will upload that.

 

[Fahad Afzal]

paper?

Oh stupid me.. forgot to mention paper:

November 11 9701/22

 

[nehaoscar]

http://freeexampapers.com/A-Level/Chemistry/CIE/2011-Jun/9701_s11_qp_21.pdf

Q 5 - b - i
Why is it electrophillic addition?
Cl has a negative charge right?
Shouldn't it be nucleophilic?

 

[The Sarcastic Retard]

Oh stupid me.. forgot to mention paper:

November 11 9701/22

4)
Butene converts into 1,2-dihydroxybutane(v).
The secondary -OH will oxidize to =O; primary -OH will oxidize to -COOH.

5b)
wait m sketching and explaining in pic.

 

[Fahad Afzal]

4)
Butene converts into 1,2-dihydroxybutane(v).
The secondary -OH will oxidize to =O; primary -OH will oxidize to -COOH.

5b)
wait m sketching and explaining in pic.

Tysm for that

 

[The Sarcastic Retard]

4)
Butene converts into 1,2-dihydroxybutane(v).
The secondary -OH will oxidize to =O; primary -OH will oxidize to -COOH.

5b)
wait m sketching and explaining in pic.

5c) writing explanation. wait here u go, 5b)

 

[Abdul Hanan]

can anyone tell me what reactions in organic section are really important? thanks..

 

[The Sarcastic Retard]

5c)
by ma frn, suchal