Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: highflier on January 08, 2011, 05:14:35 AM
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1.) What is the principle involved, type equation, sample equation, and brief explanation involved in adding drops of FORMALDEHYDE, BENZALDEHYDE, ACETALDEHYDE and ACETONE to SODIUM HYDROXIDE?
2.) A test tube with 2ml of 40% NaOH solution is added with 5 drops of bezaldehyde then submerging this tube in a water bath for 10 mins. upon removing it in water bath, we acidified it with 6N HCl.
What is the purpose of acidification of a sample with HCl?
Anyone please answer me you may submit LINKS, or anything :'( THANK YOU!
I would be grateful if you can answer atleast one of my questions :)
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We have the same problem. :/ From what section are you?
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1.) What is the principle involved, type equation, sample equation, and brief explanation involved in adding drops of FORMALDEHYDE, BENZALDEHYDE, ACETALDEHYDE and ACETONE to SODIUM HYDROXIDE?
2.) A test tube with 2ml of 40% NaOH solution is added with 5 drops of bezaldehyde then submerging this tube in a water bath for 10 mins. upon removing it in water bath, we acidified it with 6N HCl.
What is the purpose of acidification of a sample with HCl?
Anyone please answer me you may submit LINKS, or anything :'( THANK YOU!
I would be grateful if you can answer atleast one of my questions :)
Look up the Canizzaro reaction and the aldol reaction.
in question 2; HCl is used to neutralise the excess base and re-protonate one of the products.
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Look up the Canizzaro reaction and the aldol reaction.
in question 2; HCl is used to neutralise the excess base and re-protonate one of the products.
THANKS SIR. :)
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Guys, I still can't understand this. I'm sorry but can someone please answer this questions for me? It can only be an idea or something. I'll appreciate that. :)
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Guys, I still can't understand this. I'm sorry but can someone please answer this questions for me? It can only be an idea or something. I'll appreciate that. :)
Look at the answer above:
http://www.chemicalforums.com/index.php?topic=46051.0
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Deleted, I misunderstood question.
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I have the same problem too, can anyone please help me :(
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Read the thread above!
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E. Reactions of the Aldehydes and Ketones with Sodium Hydroxide
Objective:
• To determined what physical and chemical changes happen to Aldehydes and Ketones as it react with the Sodium Hydroxide
Procedures:
1. Prepare 5 clean and dry test tubes
2. Label the first 3 tubes and place 2 ml 40% NaOH solution
3. Label the remaining test tubes 4 and 5 and place 2 ml of 10% NaOH solution
4. Transfer 10 drops of the following samples: tube 1- formaldehyde, tube 2- benzaldehyde, tube 3 & 4 acetaldehyde and in tube 5 acetone
5. Transfer all tubes in a boiling water bath for 10 minutes: Note for the following changes:
6. Place some 6N HCl in tube 2 after acidification
7. Record all of your observation
Results:
Tube Sample NaOH Observations
Formaldehyde 40% Foul smell
Benzaldehyde 40% White precipitate, yellow oil on the surface of the solution
Acetaldehyde 40% Dark Orange solution with dark resin
Acetaldehyde 10% Orange Solution with red Precipitate
Acetone 10% Viscous colorless Solution
Interpretation of Results:
After adding
Reagents used:
• Sodium Hydroxide solution
• HCl
a.) State the function of the sodium hydroxide in the test
b.) What are the principles involved in the test? What is its purpose
• Cannizzaro reaction is a redox reaction in which two molecules of an aldehyde are reacted to produce a primary alcohol and a carboxylic acid using a hydroxide base. It involves a reaction with aldehydes which have no alpha hydrogen atoms
Aldol Condesation is an organic reaction in whichan enolate ion reacts with a carbonyl compound to form a β-hydroxyaldehyde or β-hydroxyketone, followed by dehydration to give a conjugated enone
•
c.) Provide the type equation used in the test
d.) Show the sample equations involved in the reaction between:
• 40% Sodium Hydroxide and your samples which gave a positive result
• 10% Sodium Hydroxide and your samples which gave a positive result
e.) Provide a possible explanation for
• Positive result obtained with your sample
• Negative results obtained with your samples
f.) What is the purpose of acidification with HCL
HCl is used to neutralize the excess base and to re-protonate one of the products
please answer the following, im begging all of you.please don't ignore this. :'( :'(
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Why should we do all the work for you?
Forum rules state you must show your own attempt.
I suggest you start with one question at a time, otherwise the whole thing will get very confusing.