Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

41.

The following data is obtained during the first order thermal decomposition of 2A(g)→ B(g) +C(s) at constant volume and temperature.

S.No Time Total pressure in Pascal
1. At the end of 10 min 300
2. After completion 200

The rate constant in min-1

  • 0.0693

  • 6.93

  • 0.00693

  • 69.3


42.

Which one of the following is an example for homogeneous catalysis?

  • Manufacture of sulphuric acid by Contact process

  • Manufacture of ammonia by Haber's process

  • Hydrolysis of sucrose in presence of dilute hydrochloric acid

  • Hydrogenation of oil


43.

A white crystalline salt A reacts with dilute HCl to liberate a suffocating gas B and also forms a yellow precipitate. The gas B turns potassium dichromate acidified with dilute H2SO4 to a green coloured solution C. A, B, C are respectively

  • Na2SO3, SO2, Cr2(SO4)3

  • Na2S2O3, SO2, Cr2(SO4)3

  • Na2SO2 , SO2, Cr2(SO4)3

  • Na2SO4, SO2, Cr2(SO4)3


44.

Molecules of a noble gas do not possess vibrational energy because a noble gas

  • is monoatomic

  • is chemically inert

  • has completely filled shells

  • is diamagnetic


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45.

E1, E2, E3 are the emf values of the three galvanic cells respectively.

(i)Zn| Zn1M2+|| Cu0.1M2+|Cu(ii)Zn| Zn1M2+|| Cu1M2+|Cu(iii)Zn| Zn0.1M2+|| Cu1M2+|Cu

Which one of the following is true?

  • E1> E>E3

  •  E>E>E1

  • E>E2 > E1

  • E1> E3 >E2


46.

Out of the compounds below the vapour pressure of (B) at a particular temperature is

                     

  • higher than that of (A)

  • lower than that of (A)

  • higher or lower than (A), depending on the size of the vessel

  • same as that of (A)


47.

An oxygen containing organic compound upon oxidation forms a carboxylic acid as the only organic product with its molecular mass higher by 14 units. The organic compound is

  • an aldehyde

  • a primary alcohol

  • a secondary alcohol

  • a ketone


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48.

The compound obtained when acetaldehyde reacts with dilute aqueous sodium hydroxide exhibits

  • geometrical isomerism

  • optical isomerism

  • neither optical nor geometrical isomerism

  • both optical and geometrical isomerism


B.

optical isomerism

When acetaldehyde is treated with aqueous sodium hydroxide solution, it undergoes aldol condensation (because of the presence of α-H atom) as.

CH3CHO + HCH2CHO NaOHDil aqueouS CH3C*H(OH)CH2CHOaldol                                                                   (showopticalisomerism)

Since, the aldol formed contains one asymmetric carbon atom, it will show optical
isomerism. On heating, aldol loses water and gives an alkene.

CH3CH(OH)CH2CHO  CH3CH=CHCHO(show geometrical isomerism) 


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49.

Which one of the following has the most nucleophilic nitrogen?


50.

The correct sequence of reactions to convert p-nitrophenol into quinol involves

  • reduction, diazotization and hydrolysis

  • hydrolysis, diazotization and reduction

  • hydrolysis, reduction and diazotization

  • diazotization, reduction and hydrolysis


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