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OCR F324-June 2013 Chemistry

Reply 2060

Yh true
Hey you know with the reaction of halogenoalkanes and amines?
Why is ethanol the solvent?
Also,excess ammonia is added to prevent further substitution,right?

Original post by _HabibaH_

I really don't know.

HEY DOES ANYONE KNOW THE ANSWER TO THIS PLEASE? THANK YOU!

You really shouldn't need to know why ethanol is used as a solvent, it just is!

And yes, excess to minimise further substitutions.

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Reply 2061

_HabibaH_

8

Original post by otrivine

but from primary to aldehyde there is water

and from aldehyde or cooh to primary there is no water formed

From an ALDEHYDE to a CARBOXYLIC ACID there is NO WATER
From an ALCOHOL TO A KETONE/CARBOXYLIC ACID/ALDEHYDE there is WATER PRESENT

In all REDUCTION REACTIONS, there is NO WATER, only OH- where H2O is the solvent.

Reply 2062

_HabibaH_

8

Original post by varsh05

it does say in the textbook that excess ammonia is used to minimise further substitution.
Not too sure about the ethanol one though..

Original post by d4rth

you really shouldn't need to know why ethanol is used as a solvent, it just is!

And yes, excess to minimise further substitutions.

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thanks to you both :smile:

Reply 2063

otrivine

OP

14

Original post by _HabibaH_

From an ALDEHYDE to a CARBOXYLIC ACID there is NO WATER
From an ALCOHOL TO A KETONE/CARBOXYLIC ACID/ALDEHYDE there is WATER PRESENT

In all REDUCTION REACTIONS, there is NO WATER, only OH- where H2O is the solvent.

Thank you and sorry :smile:

Questions anyone?

Jan 2012, one question was about oxidising and reducing alcohols and carboxylic acid. The question was fine but about reducing carboxylic acid, is it always straight to-OH?
Do we need to know the mechanism? I find trying to think of the mechanism so confusing as there is initially 2 O atoms(in the carboxylic acid group)

Reply 2066

Lysipud

1

Could someone please explain to me question 4bii from January 2012.

Reply 2067

otrivine

OP

14

Original post by MathsNerd1

Questions anyone?

sure

What are the two main factors that allows efficient separation

Reply 2068

kuku2013

hey what mark is usually 90ums (full marks)

Reply 2069

_HabibaH_

8

Original post by otrivine

Thank you and sorry :smile:

Don't worry about it. What helps you, will help all of us. :biggrin:

Reply 2070

otrivine

OP

14

Original post by _HabibaH_

Don't worry about it. What helps you, will help all of us. :biggrin:

thanks

and what is the systematic name for the diazonium ion?

or do we just call it diazonoum ion and what about the azo dye?

Reply 2071

MathsNerd1

17

Original post by otrivine

sure

What are the two main factors that allows efficient separation

Is this relative solubility and adsorption too?

Reply 2072

Zzzyax

2

do amines react with alcohols?

Reply 2073

otrivine

OP

14

Original post by MathsNerd1

Is this relative solubility and adsorption too?

yup correct

my turn

Reply 2074

MathsNerd1

17

Original post by otrivine

thanks

and what is the systematic name for the diazonium ion?

or do we just call it diazonoum ion and what about the azo dye?

Isn't it benzenediazonium chloride? But I'd leave it as a diazonium ion really :tongue:

Reply 2075

otrivine

OP

14

Original post by Zzzyax

do amines react with alcohols?

they can right? because water can be removed ?

Reply 2076

GoldenCakes02

Original post by D4rth

Its just an application question that's been thrown in to make you think in the exam. You shouldn't need any prior knowledge and I doubt they would ask again.

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Original post by _HabibaH_

It was in Jan 2012. You may have to learn about it. It's basically just application. A cyclic structure is formed whilst a condensation reaction takes place between the amine/carboxyl groups.