Class 12 Chemistry - Chapter Aldehydes Ketones and Carboxylic Acids NCERT Solutions | An organic compound (A) (molecular formu

Give simple chemical tests to distinguish between the following pairs of compounds.

(i) Propanal and Propanone

(ii) Acetophenone and Benzophenone

(iii) Phenol and Benzoic acid

(iv) Benzoic acid and Ethyl benzoate

(v) Pentan-2-one and Pentan-3-one

(vi) Benzaldehyde and Acetophenone

(vii) Ethanal and Propanal

Which of the following compounds would undergo aldol condensation, which the Cannizzaro reaction and which neither? Write the structures of the expected products of aldol condensation and Cannizzaro reaction.

(i) Methanal                       (ii) 2-Methylpentanal

(iii) Benzaldehyde              (iv) Benzophenone

(v) Cyclohexanone             (vi) 1-Phenylpropanone

(vii) Phenylacetaldehyde     (viii) Butan-1-ol

(ix) 2, 2-Dimethylbutanal

How will you convert ethanal into the following compounds?

(i) Butane-1, 3-diol  (ii) But-2-enal  (iii) But-2-enoic acid

Arrange the following compounds in increasing order of their reactivity in nucleophilic addition reactions.

(i)Ethanal, Propanal, Propanone, Butanone.

(ii)Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.

Hint:Consider steric effect and electronic effect.

Write the structures of the following compounds.

(i) α-Methoxypropionaldehyde

(ii) 3-Hydroxybutanal

(iii) 2-Hydroxycyclopentane carbaldehyde

(iv) 4-Oxopentanal

(v) Di-sec-butyl ketone

(vi) 4-Fluoroacetophenone

Arrange the following compounds in increasing order of their property as indicated:

(i) Acetaldehyde, Acetone, Di-tert-butyl ketone, Methyl tert-butyl ketone (reactivity towards HCN)

(ii) CH₃CH₂CH(Br)COOH, CH₃CH(Br)CH₂COOH, (CH₃)₂CHCOOH, CH₃CH₂CH₂COOH (acid strength)

(iii) Benzoic acid, 4-Nitrobenzoic acid, 3,4-Dinitrobenzoic acid, 4-Methoxybenzoic acid (acid strength)

Describe the following:

(i) Acetylation

(ii) Cannizzaro reaction

(iii) Cross aldol condensation

(iv) Decarboxylation

Give plausible explanation for each of the following:

(i) Cyclohexanone forms cyanohydrin in good yield but 2, 2, 6 trimethylcyclohexanone does not.

(ii) There are two -NH₂ groups in semicarbazide. However, only one is involved in the formation of semicarbazones.

(iii) During the preparation of esters from a carboxylic acid and an alcohol in the presence of an acid catalyst, the water or the ester should be removed as soon as it is formed.

Which acid of each pair shown here would you expect to be stronger?

(i) CH₃CO₂H or CH₂FCO₂H

(ii)CH₂FCO₂H or CH₂ClCO₂H

(iii) CH₂FCH₂CH₂CO₂H or CH₃CHFCH₂CO₂H

(iv)

Predict the products formed when cyclohexanecarbaldehyde reacts with following reagents.

(i) PhMgBr and then H₃O⁺

(ii)Tollens' reagent

(iii) Semicarbazide and weak acid

(iv)Excess ethanol and acid

(v) Zinc amalgam and dilute hydrochloric acid

For the reaction R → P, the concentration of a reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.

Write the formulas for the following coordination compounds:

(i) Tetraamminediaquacobalt (III) chloride

(ii) Potassium tetracyanonickelate(II)

(iii) Tris(ethane-1,2-diamine) chromium(III) chloride

(iv) Amminebromidochloridonitrito-N-platinate(II)

(v) Dichloridobis(ethane-1,2-diamine)platinum(IV) nitrate

(vi) Iron(III) hexacyanoferrate(II)

(i) Write structures of different isomeric amines corresponding to the molecular formula, C4H11N

(ii) Write IUPAC names of all the isomers.

(iii) What type of isomerism is exhibited by different pairs of amines?

Why are solids rigid?

Write any two characteristics of Chemisorption.

Which of the ores mentioned in Table 6.1 can be concentrated by magnetic separation method?

Why are pentahalides more covalent than trihalides?

Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?

Glucose or sucrose are soluble in water but cyclohexane or benzene (simple six membered ring compounds) are insoluble in water. Explain.

Write structures of the following compounds:

(i) 2-Chloro-3-methylpentane

(ii) 1-Chloro-4-ethylcyclohexane

(iii) 4-tert. Butyl-3-iodoheptane

(iv) 1,4-Dibromobut-2-ene

(v) 1-Bromo-4-sec. butyl-2-methylbenzene

What is meant by positive & negative deviations from raoult’s law & how is the sign of ΔmixH related to positive & negative deviations from Raoult’s law?

Define conductivity and molar conductivity for the solution of an electrolyte. Discuss their variation with concentration.

Why does the conductivity of a solution decrease with dilution?

Write the mechanism of acid-catalysed dehydration of ethanol to yield ethene.

Distinguish between

(i)Hexagonal and monoclinic unit cells

(ii) Face-centred and end-centred unit cells.

What are alloys? Name an important alloy which contains some of thelanthanoid metals. Mention its uses.

Which alkyl halide from the following pairs would you expect to react more rapidly by an S_N2 mechanism? Explain your answer.

Arrange the compounds of each set in order of reactivity towards SN2 displacement:

(i) 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane

(ii) 1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 3-Bromo-2- methylbutane

(iii) 1-Bromobutane, 1-Bromo-2,2-dimethylpropane, 1-Bromo-2-methylbutane, 1-Bromo-3-methylbutane.

Write the structure of the major organic product in each of the following reactions:

Copper crystallises into a fcc lattice with edge length 3.61 x 10^-8cm. Show that the calculated density is in agreement with its measured value of 8.92 g cm^-3.