Chemistry: Post your doubts here!

[robinhoodmustafa]

First tell me that can I right Co2 instead of Carboxylic Acid when Alkene undergoes reaction with KMNO4 hot concentrated. because like the end product of hot Kmno4 is always co2 gas


Secondly.. how B and C are chiral ? (written in Ms) like they dont have different functional group attached to it.

9701 paper 23 May june 2012.

Suchal Riaz

 

[Mohammed salik]

Problem is should we show the workings step by step because in some papers there are questions to calculate the moles and then the concentration in same part.
If we want we can simplify and write it down in one step like the marking scheme does. But what should we do actually simplify or write it step wise?

And another question is H2O2 a oxidising agent or a reducing agent and why?

One more, is silver sulfate a prercipitate? Because when doing a paper i thought that if their is a sulfate ion if we test that for Cl-(although it doesn't have) we might get a white precipitate if silver sulfate is ppt. and that might mislead us to thinking it has a Cl- ion.

Its Better If you Show Ur working and Be on Safe Side ..

And H2O2 is Oxidizing Agent because H2O2 itself is reduced... while reacting it loses Oxygen to form water which is reduction.
eg . 2H+(aq) + H2O2(aq)+2Fe2+(aq) -> 2Fe3+(aq) +2H2O(l)

And yes Silver sulphate is insoluble . but i dont get your question?!

 

[Mohammed salik]

First tell me that can I right Co2 instead of Carboxylic Acid when Alkene undergoes reaction with KMNO4 hot concentrated. because like the end product of hot Kmno4 is always co2 gas


Secondly.. how B and C are chiral ? (written in Ms) like they dont have different functional group attached to it.
View attachment 40722
9701 paper 23 May june 2012.
Suchal Riaz

But if You read the question carefully it says Write the Formula of ORGANIC Product.. so CO2 is Not ORGANIC

Plz look at attachments.. (I m Sorry For Bad Drawing )

 

[Browny]

Its Better If you Show Ur working and Be on Safe Side ..

And H2O2 is Oxidizing Agent because H2O2 itself is reduced... while reacting it loses Oxygen to form water which is reduction.
eg . 2H+(aq) + H2O2(aq)+2Fe2+(aq) -> 2Fe3+(aq) +2H2O(l)

And yes Silver sulphate is insoluble . but i dont get your question?!

Thanks.

So basically your are saying to write all the working step by step without joining them into one step huh?

OK, the other question is say there is a a salt having both a Cl- and a sulfate ion, how do we confirm it has a Cl- ion?
Because if we test with AgNO3 we will anyway get a precipitate with both the 2 anions.

 

[robinhoodmustafa]

But if You read the question carefully it says Write the Formula of ORGANIC Product.. so CO2 is Not ORGANIC

Plz look at attachments.. (I m Sorry For Bad Drawing )

Oh! mistake.

I got it thankyou.

 

[robinhoodmustafa]

1-View attachment 40694

2-View attachment 40695

3-View attachment 40696

4-View attachment 40697

Anybody help me in this.

Suchal Riaz

Mohammed salik

 

[Mohammed salik]

Mohammed salik

I Could'nt Understand Frst 2 Attachements.. It would be better if u Post year and Question!

 

[Mohammed salik]

Mohammed salik

Thanks.

So basically your are saying to write all the working step by step without joining them into one step huh?

OK, the other question is say there is a a salt having both a Cl- and a sulfate ion, how do we confirm it has a Cl- ion?
Because if we test with AgNO3 we will anyway get a precipitate with both the 2 anions.

Much Better Question this Time...
You could Use Silver then Do conformatory test with Ammonia.. only Chloride Is Soluble..
Or You could use Barium Compound.. which gives Ppt with Sulphate Ion only !

 

[robinhoodmustafa]

I Could'nt Understand Frst 2 Attachements.. It would be better if u Post year and Question!

no year on them

 

[Marwaa]

can someone explain to me the difference between calculating the amount ,in moles, of hydrogen atoms and hydrogen molecules?

 

[Mohammed salik]

can someone explain to me the difference between calculating the amount ,in moles, of hydrogen atoms and hydrogen molecules?

Hydrogen Atoms Would only be H...
Hydrogen Molecule Would Be H2!!

 

[Mohammed salik]

no year on them

So Which two compounds Should we compare for Boilling points?
Is 1 st liked to Second?
If Yes the my ans would be :
(i) both have very similar van der Waals’ forces (due to number of electrons).
(ii) CH3F has permanent dipole . Due to electronegativity difference between them!

 

[Marwaa]

Hydrogen Atoms Would only be H...
Hydrogen Molecule Would Be H2!!

you think i dont know that? i meant difference in calculating them

 

[Mohammed salik]

you think i dont know that? i meant difference in calculating them

Haha..
H2 would have Atomic mass of 2.. H would have atomic mass of 1!!

 

[Suchal Riaz]

Could you pls pls explain a bit further as to why it can't be methyl ethanoate, Or propyl ethanoate, hence leaving ethyl ethanoate as the only option? thanks!

no problem.
let's consider two cases in detail:

 

[Browny]

Much Better Question this Time...
You could Use Silver then Do conformatory test with Ammonia.. only Chloride Is Soluble..
Or You could use Barium Compound.. which gives Ppt with Sulphate Ion only !

So then how do we test for the Cl- ion then? For that we must use AgNO3 right? Then when we add ammonia the AgCl ppt. would dissolve but then the AgSO4 ppt. would remain and we would not know whether the ppt actually did dissolve or not?

 

[Browny]

By looking at the test tube !!

What do you mean?

 

[Mohammed salik]

What do you mean?

If you are not sure then test for Sulphate First using Barium Ions and if it Gives white ppt then use stong acid if its insoluble it means Its Sulphate for Sure..!!

 

[Browny]

but barium chloride is also a ppt. it is given as a standard test for Cl-.
And also how can we see solubility when ppt of sulfate is left?

 

[Mohammed salik]

but barium chloride is also a ppt. it is given as a standard test for Cl-.
And also how can we see solubility when ppt of sulfate is left?

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