Chemistry: Post your doubts here!

[nehaoscar]

NaCl is expected to have a lower mp/bp than KCl, as mp/bp is inversely proportional to the ionic radii.

In other words, the larger the ions, the lower the mp/bp.

But KCl has a higher mp than NaF? - down the group mp and bp increase for halogens so why not A?

 

[hassannouman]

Doesn't the OCO represent an ester?
And also the question says that ethyl ethanoate is produced
View attachment 54519

oh yes, it's an ester, lol sorry, it's not esterification as ester is not produced using carboxylic acid, secondary alcohol CH3CH2OCH(OH)CH3 is oxidised to produce ketone which makes ester (ethyl ethanoate)

 

[shazmina]

Can any1 please help me with this question ........

 

[Metanoia]

But KCl has a higher mp than NaF? - down the group mp and bp increase for halogens so why not A?

KCl vs NaF is ionic bonding. Depends on ionic radius and charge of ions.

Halogens is VDW forces of attraction. Depends on size of electron clouds.

 

[nehaoscar]

KCl vs NaF is ionic bonding. Depends on ionic radius and charge of ions.

Halogens is VDW forces of attraction. Depends on size of electron clouds.

So but then why is option A wrong?

 

[Metanoia]

So but then why is option A wrong?

As explained, NaF is expected to have higher mp than KCl.

Sorry, realized I made a typo in my compounds in the earlier posts, i have amended them.

 

[nehaoscar]

Why is 2 wrong?

 

[nehaoscar]

As explained, NaF is expected to have higher mp than KCl.

Sorry, realized I made a typo in my compounds in the earlier posts, i have amended them.

Hahah okay no problem! That's why i was confused Thanks!

 

[Metanoia]

Perhaps you can say why you think A is correct?

View attachment 54527
Why is 2 wrong?

CHO on 2 can be oxidized to COOH. However the benzene ring causes it to be poorly soluble in water.

 

[Falconwing]

http://freeexampapers.com/A-Level/Chemistry/CIE/2013-Jun/9701_s13_qp_12.pdf

Q25 - Answer is D. Why not C? Why do the double bonds not form with the carbon with OH group anyway?

 

[nehaoscar]

How D... and what is the bond angle for Cl2 (option C)?

 

[nehaoscar]

 

[nehaoscar]

 

[nehaoscar]

What does the reaction with NaHCO3 usually give?
Is it like nascent O or H or something?

 

[nehaoscar]

How to do this one??

 

[fantastic girl]

What does the reaction with NaHCO3 usually give?
Is it like nascent O or H or something?

3 - wrong since there is no acid grp

 

[nehaoscar]

What would each one give?

 

[nehaoscar]

Isn't it aluminium that is dimeric covalent?
But then why is answer B :/

 

[Metanoia]

http://freeexampapers.com/A-Level/Chemistry/CIE/2013-Jun/9701_s13_qp_12.pdf

Q25 - Answer is D. Why not C? Why do the double bonds not form with the carbon with OH group anyway?

During dehydration, the OH is removed with a neighboring H atom (either the red dot or blue dot).


Removing the OH and H atom at the red dot gives us option D.

 

[fantastic girl]

What would each one give?

C is it ?
when ever an ammonium salt reacts with an alkali/base u get ammonia gas given off.....make sure u know this!