Science (English Medium) इयत्ता १२ - CBSE Important Questions for Chemistry

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

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

H₂O

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

CH₃CH₂OH

Arrange the following:

Aniline, p-nitroaniline, p-methylaniline - in the increasing order of their basic strength

Why does NH₃ act as a Lewis base?

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

Write the IUPAC name of the following compound and classify it as primary, secondary and tertiary amine.

CH₃NHCH(CH₃)₂

Write the IUPAC name of the following compound and classify it as primary, secondary and tertiary amine.

(CH₃CH₂)₂NCH₃

Account for the following:

Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.

Arrange the following:

In increasing order of basic strength:

C₆H₅NH₂, C₆H₅NHCH₃, C₆H₅CH₂NH₂

Write a short note on diazotisation.