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’sreagent while compounds “C” and “D” do not. Both “B” and “C” give a yellow precipitate whenheated with iodine in the presence of NaOH. Compound “D” gives brisk effervescence with sodiumbicarbonate solution. Identify “A”, “B”, “C” and “D” given the number of carbon atoms in three ofthese carbon compounds is three while one has two carbon atoms. Give an explanation for y ouranswer.
Question
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’sreagent while compounds “C” and “D” do not. Both “B” and “C” give a yellow precipitate whenheated with iodine in the presence of NaOH. Compound “D” gives brisk effervescence with sodiumbicarbonate solution. Identify “A”, “B”, “C” and “D” given the number of carbon atoms in three ofthese carbon compounds is three while one has two carbon atoms. Give an explanation for y ouranswer.
Solution
The given reactions suggest that compounds A, B, and C are carbonyl compounds as they form an orange-red precipitate with 2,4-DNP reagent. This test is specific for carbonyl compounds.
Compounds A and B reduce Tollen's reagent, indicating they are aldehydes because aldehydes can be oxidized to carboxylic acids, but ketones cannot. Therefore, A and B are aldehydes.
Compounds B and C give a yellow precipitate when heated with iodine in the presence of NaOH, which is a positive iodoform test. This test is positive for methyl ketones and secondary alcohols that can be oxidized to methyl ketones. Therefore, B is a methyl aldehyde and C is a methyl ketone.
Compound D gives brisk effervescence with sodium bicarbonate solution, indicating it is a carboxylic acid because only carboxylic acids react with sodium bicarbonate to produce carbon dioxide gas.
Given the number of carbon atoms in three of these carbon compounds is three while one has two carbon atoms, we can identify:
A as Propanal (an aldehyde with 3 carbon atoms) B as Acetaldehyde (an aldehyde with 2 carbon atoms) C as Acetone (a ketone with 3 carbon atoms) D as Propanoic acid (a carboxylic acid with 3 carbon atoms)
Similar Questions
A compound 'A' with molecular formula C H O gave positive 2, 4-DNP test but a negative Tollen'sreagent test. It was oxdised to carboxylic acid 'B' with molecular formula C H O when treated withalkaline KMnO under vigorous condition. Sodium salt of 'B' gave a hydrocarbon 'C' on Kolbe'selectrolytic reduction. Identify A, B and C and write the chemical equations for the reaction.
An organic compound [A] which has characteristic odour, reacts with conc. NaOH togive two compounds [B] and [C]. Compound [B] has molecular formula C7H8O whichupon oxidation gives back compound [A]. Compound [C] is the sodium salt of the acidand upon treatment with sodalime yields an aromatic hydrocarbon [D]. Identify thecompounds [A], [B], [C] and [D].
An organic compound (A) having molecular formula C H O gives a characteristic colour with aqueousFeCl solution. (A) on treatment with CO and NaOH at 400 K under pressure gives (B), which onacidification gives a compound (C). The compound (C) reacts with acetyl chloride to give (D) which is apopular pain killer.The following questions are multiple choice questions. Choose the most appropriate answer:(i) Compound (A) is(a) 2-hexanol(b) dimethylether(c)phenol(d) 2-methylpentanol.(ii) Number of carbon atoms in compound (D) is(a) 7 (b) 6 (c) 8 (d) 9(iii) The conversion of compound (A) to (C) is known as(a) Reimer-Tiemann reaction(b) Kolbe'sreaction(c) Schimdtreaction(d) Swartsreaction(iv) Compound (A) on heating with compound (C) in presence of POCl gives a compound (D) which isused(a) in perfumery as aflavouring agent(b) as anantipyretic(c) as ananalgesic(d) as an intestinalantiseptic
Compound C is a single organic biomolecule with an important role in plant metabolism.Solutions of C in four separate test tubes yield the following results when combined with thereagents listed:Ninhydrin - BlueBiuret reagent - BlueTollens' reagent - ClearLugol's solution - BrownAddition of a hydrolytic enzyme to a fresh tube of compound C results in a solution that, whencombined with Tollen's reagent, forms a silvery precipitate. Which of the following is a possibleidentity for Compound C?A. Amino acid; serine.B. Monosaccharide; glucose.C. Peptide; glutathioneD. Disaccharide; sucrose.E. Polysaccharide; amylose
When an aldehyde reacts with Tollens' reagent, what is the product formed?a. Silver mirrorb. Red precipitatec. Green colord. No reaction
Upgrade your grade with Knowee
Get personalized homework help. Review tough concepts in more detail, or go deeper into your topic by exploring other relevant questions.