Chemistry: Post your doubts here!

[ahmedish]

Guys in june 13 v23 5 a iv how did we get a dioic? does KMnO4 oxidise primary alcohols to acids?

 

[qwertypoiu]

Guys in june 13 v23 5 a iv how did we get a dioic? does KMnO4 oxidise primary alcohols to acids?

Yes, hot concentrated KMnO4 can oxidise alcohols.
However, cold one cannot.
Also note that K2Cr2O7 cannot break a double bond.

 

[ahmedish]

Yes, hot concentrated KMnO4 can oxidise alcohols.
However, cold one cannot.
Also note that K2Cr2O7 cannot break a double bond.

Thanks man.

 

[ahmedish]

http://freeexampapers.com/A-Level/Chemistry/CIE/2010-Jun/9701_s10_qp_22.pdf
For Question 4 part c can one of the esters of C4H8O2 he CH3CO2(CH3)CH3? please someone help!??

No, CH3CO2(*C*H3)CH3 this carbon will be bonded to 5 that way, 3 hydrogen atoms, 1 oxygen atom, 1 carbon atom.

 

[ahmedish]

Reaaction bw CH3CO2CH(CH30)2 with KOH(aq) warm? What type of reacton is this and whats the product?

basic hydrolysis giving ethanoate salt and alcohol

 

[NIM]

Guyzzz I need help for 7 d part
9701/42/O/N/13

 

[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