Question

I need help with writing the conclusion for this online lab report

Abstract
By testing the unknown substance with different chemicals such as NaOH, NaHCO3, FeCl3, HCl, Sodium Nirtite, Methanol, Alchol, Borsches’s reaggent, Schiffs reagent by process of elimation we are able to find out the functional group of the substance. The reactions that occur will help us to distinguish which functional group the unknown substance belongs to

Materials:
Test Tubes- 6
Gloves
Droppers
Spoon (for unknown substance)
Waterbath - one cold/ one hot
Chemicals- NaOH, NaHCO3, FeCl3, HCl, Sodium Nirtite, Methanol, Alchol, Borsches’s reaggent, Schiffs reagent
Lab coat

Methods :

Take a spoonful of the unknown substance and add it to a test tube. Test it for amides by adding NaOH.
Repeat this step adding NaHCO3 and shake the bottle well to test the unknown substance for acids.
Add the unknown substance to a test tube and add alcohol to the test tube. Then add FeCl3.
Take a spoonful of the unknown substance and add it to a test tube. Add methanol. Then add some of the borsches’s reaggent. Place it in a warm water bath for re-boiling
Take a spoonful of the unknown substance and add some Schiffs reagent. Shake the test tube well
Take a spoonful of the unknown substance and add HCl. Place the test tube in an ice water bath. Once cold add some sodium nitrite.

Results:

By testing the unknown substance for amides by adding NaOH the substance dissolved. This shows us that there was a presence of acidic substances in the unknown substance. Then the unknown substance was tested for acids by adding NaHCO3 and when shaken the substance was still present at the bottom of the tube which shows that acids are present in the unknown substance. Next phenols were tested in the unknown substance by the addition of alcohol and FeCl3. Because this mixture would produce a violet color and no color was produced we can conclude that there was an absense of phenols in the unknown substance. By taking another sample of the unknown substance and adding methanol as well as borsche’s reaggent and putting the test tube in a warm water bath for boiling there was an absense of aldehydes and ketones. The sample was then tested for Aldehydes by adding schiffs reagent and no violet color developed confirming there was an absense of aldehydes in the unknown substance. Lastly the unknown sample was tested for primar aliphatic amines by adding HCl and put into a cold water bath. Then sodium nitrite was added. The sample began to foam which means there was a presence of primart aliphatic amines in the unknown sample.

Data:

Unknown
Added NaOH
Substance dissolved
Presence of acidic substances
Unknown
Add NaHCO3
Bubbles
Presence of acids
Unknown
Add Alcohol/FeCl3
No violet color
Absense of phenols
Unknown
Add Methanol/ B.reaggent/waterbath(warm)

Absense of Aldehydes/ ketones
Unknown
Add Schiffs reaggent/shake bottle
No violet color developed
Absesnse of Aldehydes
Unknown
Add HCl/ cold water bath/ add sodium nitrite

Presense of Amines

Conclusion:?

Answer 1

The experimentation done to find out the presence of functional group in the given unknown compound. On addition of NaOH, the amide group reacts with NaOH and gives off ammonia gas and sodium salt of carboxylic acid. Bubbles can be seen on addition of NaHCO₃ due to the evolution of CO₂ gas. Both of this shows the presence of acidic substance. Since there is no phenol group, addition of alcohol and FeCl₃ to the unknown substance does not produce any violet coloration as there is no formation of complex [Fe(OC₆H₅)]^3-. Hence, phenol is absent. On performing Borsche test by adding 2,4-dinitrophenyl derivative(Borsche's reagent), no positive result was seen which shows absence of aldehyde or keto group present in the unknown compound. To further confirm the  absence of aldehyde group, performed schiff's test . No violet coloration was observed. To unknown substance, added HCl and sodium nitrate while keeping it in cold water bath leads to formation of diazotisation reaction. Diazonium salt is formed the result of this reaction. This shows the presence of primary amine.