Advertisements
Advertisements
Question
Give a simple chemical test to distinguish between the following pair of compounds:
Benzaldehyde and Acetophenone
Advertisements
Solution
Tollen’s Test: Aldehydes respond to Tollen’s test. Benzaldehyde, being an aldehyde, reduces Tollen’s reagent to give a red-brown precipitate of Cu2O, but acetophenone, being a ketone, does not.
\[\ce{\underset{acetophenone}{C6H5COCH3} + \underset{Hypoiodite}{\underset{Sodium}{3NaOI}}->\underset{Benzoate}{\underset{Sodium}{C6H5COONa}} + \underset{(Yellow ppt)}{\underset{Iodoform}{CHI3}} + 2NaOH}\]
Iodoform test: Acetophenone, being a methyl ketone, undergoes oxidation by sodium hypoiodite (NaOI) to give a yellow ppt. of iodoform. However, benzaldehyde does not respond to this test.
\[\ce{\underset{Acetophenone}{C6H5COCH3} + \underset{hypoiodite}{\underset{Sodium}{3NaOI}}->\underset{benzoate}{\underset{Sodium}{C6H5COONa}} + \underset{(yellow ppt)}{\underset{iodoform}{CHI3}} + 2NaOH}\]
\[\ce{\underset{Benzaldehyde}{C6H5CHO} + NaOI -> No yellow ppt of CHI3}\]
APPEARS IN
RELATED QUESTIONS
Give a simple chemical test to distinguish between the following pair of compounds:
Ethanal and Propanal
Distinguish between: CH3COOH and HCOOH
A and B are two functional isomers of compound C3H6O.On heating with NaOH and I2, isomer B forms yellow precipitate of iodoform whereas isomer A does not form any precipitate. Write the formulae of A and B.
Propanal and Propanone
Out of CH3CH2 – CO – CH2 – CH3 and CH3CH2 – CH2 – CO – CH3, which gives iodoform test?
How will you convert ethanal into the following compound?
But-2-enoic acid
Give a simple chemical test to distinguish between the following pair of compounds:
Pentan-2-one and Pentan-3-one
Complete the synthesis by giving missing starting material, reagent or product.
Which of the following compounds gives a positive Tollen's test but negative Fehling's test?
Acetone and acetaldehyde are differentiated by
Acetaldehyde cannot show?
Which among the above compound/s does/do not form Silver mirror when treated with Tollen's reagent?
The major products formed in the following reaction sequence A and B are:
The correct set of products obtained in the following reactions:
- \[\ce{RCN ->[reduction]}\]
- \[\ce{RCN ->[(i) CH3MgBr][(ii) H2O]}\]
- \[\ce{RNC ->[hydrolysis]}\]
- \[\ce{RNH2 ->[HNO2]}\]
The reagent that can be used to distinguish acetophenone and benzophenone is ______.
An organic compound 'A' with molecular formula C5H8O2 is reduced to n-pentane with hydrazine followed by heating with NaOH and glycol. 'A' forms a dioxime with hydroxylamine and gives a positive iodoform and Tollen's test. Identify 'A' and give its reaction for iodoform and Tollen's test.
You are given four organic compounds “A”, “B” , “C” and “D”. The compounds “A”, “B” and “C” form an orange-red precipitate with 2, 4 DNP reagent. Compounds “A” and “B” reduce Tollen’s reagent while compounds “C” and “D” do not. Both “B” and “C” give a yellow precipitate when heated with iodine in the presence of NaOH. Compound “D” gives brisk effervescence with sodium bicarbonate solution. Identify “A”, “B”, “C” and “D” given the number of carbon atoms in three of these carbon compounds is three while one has two carbon atoms. Give an explanation for our answer.
Match List-I with List-II:
| List-I (Reaction) |
List-II (Reagents/Condition) |
||
| A. |  |
I. |  |
| B. |  |
II. | CrO3 |
| C. |  |
III. | KMnO4/KOH, Δ |
| D. |  |
IV. | (i) O3 (ii) Zn-H2O |
Choose the correct answer from the options given below:
Fehling’s solution ‘A’ is ______.
