Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

31.

Carbocation as an intermediate is likely to be formed in the reaction

  • Propene + Cl2 hv 2-chloropropane

  • Acetone + HCN -OH acetonecyano hydrin

  • Ethylbromide + aq.KOH  ethyl alcohol

  • Hexane anhy. AlCl3/ HCl 2-methyl pentane


32.

The IUPAC name of 'B' is

  • 3-methylbutan-2-ol

  • 2-methylbutan-3-ol

  • 2-methylbutan-2-ol

  • pentan-2-ol


33.

The correct sequence of reactions to be performed to convert benzene into m-bromoaniline is

  • nitration, reduction, bromination

  • bromination, nitration, reduction

  • nitration, bromination, reduction

  • reduction, nitration, bromination


34.

The compound that reacts the fastest with sodium methoxide is


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35.

The correct statement is

  • Cyclohexadene and cyclohexene cannot be isolated with ease during controlled hydrogenation of benzene

  • One mole each of benzene and hydrogen when reacted gives 1/3 mole of cyclohexane and 2/3 mole unreacted hydrogen

  • Hydrogenation of benzene to cyclohexane is an endothermic process

  • It is easier to hydrogenate benzene when compared to cyclohexene


A.

Cyclohexadene and cyclohexene cannot be isolated with ease during controlled hydrogenation of benzene

On controlled hydrogenation of benzene with group I metal (like Na, Li) and methanol (or ethanol) in liquid NH3, it reduces into cyclohexadiene and cyclohexene, which cannot be isolated.

This is because the presence of reducing agent hexadene is further reduced to hexene hence, statement (a) is correct. Statement (b) is incorrect due to data insufficiency. Statement (d) is incorrect because benzene is a stable aromatic compound while cycloohexene can be easily hydrogenated due reactive double bond. So correct choice is (a).


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36.

The statement that is not correct is

  • Hypophosphorous acid reduces silver nitrate to silver

  • In solid state PCl5 exists as [PCl4]+ [PCl6]-

  • Pure phosphine is non-inflammable

  • Phosphorous acid on heating disproportionates to give metaphosphonic acid and phosphine


37.

In which one of the pairs of ion given, there is an ion that forms a coordination compound with both aqueous sodium hydroxide and ammonia and an other ion that forms a coordination compound only with aqueous sodium hydroxide?

  • Pb2+, Cu2+

  • Zn2+, Al3+

  • Cu2+, Zn2+

  • Al3+, Cu2+


38.

A crystalline solid X reacts with dil. HCl to liberate a gas Y. Y decolourises acidified KMnO4. When a gas 'Z' is slowly passed into an aqueous solution of Y, colloidal sulphur is obtained X and Z could be respectively

  • Na2S, SO3

  • Na2SO4, H2S

  • Na2SO3, H2S

  • Na2SO4, SO2


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39.

A solution of 1.25 of 'P' in 50 g of water lowers freezing point by 0.3°0. Molar mass of 'P' is 94. Kf(water) = 1.86 K kg mol-1. The degree of association of 'P' in water is

  • 80%

  • 60%

  • 65%

  • 75%


40.

Volume occupied by single CsCl ion pair in a crystal is 7.014 × 10-23 cm3. The smallest Cs-Cs internuclear distance is equal to length of the side of the cube corresponding to volume of one CsCl ion pair. The smallest Cs to Cs internuclear distance is nearly 

  • 4.4 Å

  • 4.3 Å

  • 4 Å

  • 4.5 Å


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