Science (English Medium) कक्षा १२ - CBSE Important Questions

Do the following conversions in not more than two steps:

CH₃COOH to CH₃COCH₃

Do the following conversions in not more than two steps:

Assertion (A): Acetic acid but not formic acid, can be halogenated in the presence of red P and Cl₂.

Reason (R): Acetic acid is a weaker acid than formic acid.

Assertion (A): The final product in Aldol condensation is always α, β-unsaturated carbonyl compound.

Reason (R): α, β-unsaturated carbonyl compounds are stabilised due to conjugation.

Identify A and B:

What is IUPAC name of the ketone A, which undergoes iodo form reaction to give \[\ce{CH3CH = C(CH3)COONa}\] and yellow precipitate of \[\ce{CH3}\]?

Assertion (A): Strong oxidising agents oxidise toluene and its derivatives to benzoic acids.

Reason (R): It is possible to stop the oxidation of toluene at the aldehyde stage with suitable reagents.

Select the most appropriate answer from the options given below:

Out of p-tolualdehyde and p-nitrobenzaldehyde, which one is more reactive towards nucleophilic addition reactions, why?

Write the structure of the product formed when acetone reacts with 2, 4 DNP reagent.

Convert the following:

Benzene to m-nitrobenzaldehyde

Convert the following: 

Bromobenzene to benzoic acid

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.

An organic compound with molecular formula \[\ce{C7H7NO2}\] exists in three isomeric forms, the isomer ‘A’ has the highest melting point of the three. ‘A’ on reduction gives compound ‘B’ with molecular formula \[\ce{C7H9N}\]. ‘B’ on treatment with \[\ce{NaNO2/HCl}\] at 0-5° C to form compound ‘C’. On treating C with \[\ce{H3PO2}\], it gets converted to D with formula \[\ce{C7H8}\], which on further reaction with \[\ce{CrO2Cl2}\] followed by hydrolysis forms ‘E’ \[\ce{C7H6O}\]. Write the structure of compounds A to E. Write the chemical equations involved.

Account for the following:

N-ethylbenzene sulphonyl amide is soluble in alkali.

Account for the following:

Reduction of nitrobenzene using Fe and HCl is preferred over Sn and HCl.

Write the name of the reaction, structure and IUPAC name of the product formed when:

CH₃CH₂CN reacts with stannous chloride in the presence of hydrochloric acid, followed by hydrolysis.

Give the structures of A, B and C in the following reactions:

Write the major products(s) in the following:

Distinguish between the following pairs of compounds: Aniline and N-methylaniline

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

CuCN/KCN