Chemistry: Post your doubts here!

[qwertypoiu]

oh i didnt multiply it by 10 he wanted it in the distilled solution.thx mate what r u studing?a levels or as

Welcome. Doing AS this year

 

[shazmina]

I will assume you have understood the parts you did not highlight. So there would have been 42 hydrogen atoms, if it were just a straight chain alkane. We wish for only 28 to be left.
6 hydrogen atoms are accounted for by the presence of aldehyde and ring structure. So 42-6 = 36 we'd expect now.
However we wish for 28. We need to eliminate 36-28= 8 more hydrogen atoms.
Every time a double bond is added to a saturated chain, 2 hydrogen atoms are gotten rid of.
Therefore, 8/2 = 4 double bonds required to satisfy our condition.

Thanks alot JazakAllah khairan

 

[mohhef3]

someone help me out with que 30,28 and 23
http://maxpapers.com/syllabus-materials/chemistry-9701-a-level/attachment/9701_w14_qp_12/
and in que 32 what will differ in my calculations when i see that dot

 

[princess Anu]

how is 2 important in helping to reduce atmospheric pollution? :/

 

[princess Anu]

Is there an easier way to find out the number of isomers? and for this question how many are there?? Please help!!

It's 9701/13/0/N/14

whats the answer

 

[Abdel Moniem]

View attachment 54707 how is 2 important in helping to reduce atmospheric pollution? :/

Oxygen in the air reacts with sulphur dioxide to form sulphur trioxide which then reacts with calcium oxide to form calcium sulphate.

 

[princess Anu]

so this way both the pollutants i.e So3 & so2 quantities get reduced?

Oxygen in the air reacts with sulphur dioxide to form sulphur trioxide which then reacts with calcium oxide to form calcium sulphate.

 

[princess Anu]

why is C wrong?

 

[princess Anu]

how do we read the benzene rings? why is C chiral and not D?

 

[BhaiArshad]

View attachment 54717 how do we read the benzene rings? why is C chiral and not D?

Every Carbon in Benzene ring has a double bond so none of the carbons in a benzene ring are chiral. C is chiral because Central C atom is Connected to the following groups:
1) OH
2) CH3
3) Benzene Ring
4) OH Benzene Ring

4 different groups so it is chiral. Central Atom C in part D is connected to:
1) OH
2) CO2CH2CH3
3) OH Benzene Ring
4) OH Benzene Ring

 

[princess Anu]

hey you missed out the OH group attached to the benzene ring in option C (it wasn't printed properly ) .. look at the question again

 

[BhaiArshad]

hey you missed out the OH group attached to the benzene ring in option C (it wasn't printed properly )View attachment 54722 .. look at the question again

In C the Rings are different since OH is attached to different Carbon.

 

[qwertypoiu]

View attachment 54716 why is C wrong?

Pressure cannot affect Kc. Only temperature does.

 

[nehaoscar]

Why D?

 

[nehaoscar]

Why is it the same??

 

[shazmina]

View attachment 54717 how do we read the benzene rings? why is C chiral and not D?

When an OH group is directly bonded to a benzene ring it is knows as a Phenol ( you will learn this is in A2 chemistry in detail )
Therefore Option D has the Central carbon attached to two Phenols ( same group ) and thats why compound D isnt Chiral ...
Where as Compound C is attached to a phenol as well as a Benzene ring which are both different, along with Methyl and a Hydroxyl group .. Hope you understood

 

[nehaoscar]

Why C?? And Why not B??

 

[shazmina]

View attachment 54730
Why D?

Volume is inversely proportional to Pressure and Directly proportional to 1/P.. When Volume increases the pressure decreases as there will be less collision between the particles as well as with the walls of the container & Vice versa

 

[nehaoscar]

Fe(OH)2 has H-bonding then why is it insoluble??

 

[nehaoscar]

How to do this one??