Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

11.

In which of the following equilibrium Kc and Kp are not equal?

  • 2NO (g) ⇌ N2 (g)  + O2 (g)

  • SO2 (g) + NO2 (g) ⇌ SO3 (g) + NO (g)

  • H2 (g) + I2 (g) ⇌ 2 HI (g)

  • H2 (g) + I2 (g) ⇌ 2 HI (g)

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12.

Which one of the following ion has electronic configuration [Ar] 3d6?
(At. no:  Mn = 25, Fe = 26, Co = 27, Ni = 28)

  • Ni3+

  • Mn

  • Fe3+

  • Fe3+

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13.

In a buffer solution containing an equal concentration of B- and HB, the Kb for B- is 10-10.The pH of buffer solution is

  • 10

  • 7

  • 6

  • 6

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14.

Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by

  • oxidation

  • cracking

  • distillation under reduced pressure

  • distillation under reduced pressure

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15.

The tendency of BF3, BCl3 and BBr3 to behave as Lewis acid decreases in the sequence

  • BCl3 > BF3 > BBr3

  • BBr3 > BCl2 > BF3

  • BBr3 > BF3 > BCl3

  • BBr3 > BF3 > BCl3


B.

BBr3 > BCl2 > BF3

As the size of halogen atom increases, the acidic strength of boron halides increases. Thus, BF3 is the weakest Lewis acid. This is because of the pπ - pπ back bonding between the fully-filled unutilised 2p orbitals of F and vacant 2p orbitals of boron which makes BF3 less electron deficient. Such back donation is not possible in case of BCl3 or BBr3 due to the larger energy difference between their orbitals. Thus, these are more electron deficient. Since on moving are more electron deficient. Since on moving down the group the energy difference increases, Thus, the tendency to behave as Lewis acid follows the order

BBr3 > BCl3 > BF3

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16.

Which one of the following molecular hydrides acts as a Lewis acid? 

  • NH3

  • H2O

  • B2H6

  • B2H6

920 Views

17.

In the following the most stable conformation of n-butane is

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18.

Property of the alkaline earth metals that increases with their atomic number

  • the solubility of their hydroxides in water

  • the solubility of their sulphates in water

  • ionisation energy 

  • ionisation energy 

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19.

Which of the following alkaline earth metal sulphates has hydration enthalpy higher than the lattice enthalpy? 

  • CaSO4

  • BeSO4

  • BaSO4

  • BaSO4

410 Views

20.

For the reaction

straight N subscript 2 straight O subscript 5 left parenthesis straight g right parenthesis thin space rightwards arrow space 2 NO subscript 2 space left parenthesis straight g right parenthesis thin space plus space 1 half space straight O subscript 2 space left parenthesis straight g right parenthesis
the value of the rate of disappearance of N2O5 is given as 

  • 6.25 x 10-3 mol L-1s-1 and 6.25 x 10-3 mol L-1 s-1

  • 1.25 x 10-2 mol L-1s-1 and 6.25 x 10-3 mol L-1 s-1

  • 6.25 x 10-3 mol L-1s-1 and 3.125 x 10-3 mol L-1 s-1

  • 6.25 x 10-3 mol L-1s-1 and 3.125 x 10-3 mol L-1 s-1

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