Two moles of PCl5, is heated in a closed vessel of 2 L capacity.

Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

What would be the heat released when an aqueous solution containing 0.5 mole of HNO3 is mixed with 0.3 mole of OH- (enthalpy of neutralization is -57.1 k.J) ?

  • 28.5 kJ

  • 17.1 kJ

  • 45.7 kJ

  • 1.7 kJ


2.

A(g)    +  3B(g)     4C(g) .Initially concentration of A is equal to that of B. The equilibrium concentrations of A and C are equal. Kc is 

  • 0.08

  • 0.8

  • 8

  • 80


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3.

Two moles of PCl5, is heated in a closed vessel of 2 L capacity. When the equilibrium is attained 40% of it has been found to be dissociated. What is the Kc in mol/dm3?

  • 0.532

  • 0.266

  • 0.133

  • 0.174


B.

0.266

Number of moles of PCl5 dissociated at equilibrium = 2 x 40/100 = 0.8

 PCl5         PCl3   +  Cl2 2mol               0               0  (Initially)(2-0.8) mol 0.8 mol 0.8 mol (at equilibrium)[PCl5] = 1.22= 0.6ML-1[ PCl3] =  Cl2 = 0.82= 0.4 ML-1Kc = [ PCl3]   Cl2[PCl5]=0.4 × 0.40.6= 0.267 mol/dm3


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4.

How much of sulphur is present in an organic compound, if 0.53 g of the compound gave 1.158 g of BaSO4 on analysis ? 

  • 10%

  • 20%

  • 30%

  • 15%


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5.

100 g CaCO3 is treated with 1 L of 1N HCl. What would be the weight of CO2 liberated after the completion of the reaction ?

  • 55 g

  • 11 g

  • 22 g

  • 33 g


6.

The relationship between the energy E1 of the radiation with a wavelength 8000 Å and the energy E2 of the radiation with a wavelength Å 16000  is:

  • E1 = 6E2

  • E1 = 2E2

  • E1 = 4E2

  • E1 = 4E2


7.

If the molecule of HCl were totally polar, the expected value of dipole moment is 6.12 D (debye), but the experimental value of dipole moment was 1.03 D. Calculate the percentage ionic character :

  • 17

  • 83

  • 50

  • Zero


8.

Which one of the following molecules has the smallest bond angle ?

  • NH3

  • PH3

  • H2O

  • H2Se


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9.

If the absolute temperature of a gas is doubled and the pressure is reduced to one half, the volume of the gas will :

  • remain unchanged

  • be doubled

  • increase four fold

  • be halved


10.

To what temperature must a neon gas sample be heated to double its pressure, if the initial volume of gas at 75°C is decreased by 15.0%?

  • 319°C

  • 592°C

  • 128°C

  • 60°C


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