A reaction occurs spontaneously if from Chemistry NEET Year 2007

Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

The mass of carbon anode consumed (giving only carbondioxide) in the production of 270 kg of aluminium metal from bauxite by the Hall process is (Atomic mass Al= 27)

  • 180 kg

  • 270 kg

  • 540 kg

  • 90 kg


2.

The number of moles of KMnO4 reduced by one mole of KI in alkaline medium is

  • one-fifth

  • five

  • one

  • two


3.

Which of the following molecules has trigonal planar geometry?

  • IF3

  • PCl3

  • NH3

  • BF3


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4.

A reaction occurs spontaneously if

  • TS < H and both H and S are +ve

  • TS > H and both H and S are +ve

  • TS = H and both H and S are +ve

  • TS > H and H is +ve and S is - ve


B.

TS > H and both H and S are +ve

The spontaneity of reaction is based upon the negative value of G, G is based upon T, S and H according to the following equation (Gibbs-Helmholtz equation):

G = H - TS

If the magnitude of H - TS is negative, then the reaction is spontaneous.

When TS > H and H and S are +ve, then G is negative.


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5.

The correct sequence of increasing covalent character is represented by

  • LiCl < NaCl < BeCl2

  • BeCl2 < NaCl < LiCl

  • NaCl < LiCl < BeCl2

  • BeCl2 < LiCl < NaCl


6.

Which of the following pairs of a chemical reaction is certain to result in a spontaneous reaction?

  • Exothermic and decreasing disorder

  • Endothermic and increasing disorder

  • Exothermic and increasing disorder

  • Endothermic and decreasing disorder


7.

Which of the following is the electron deficient molecule?

  • B2H6

  • C2H6

  • PH3

  • SiH4


8.

A nuclide of an alkaline earth metal undergoes radioactive decay by emission of three α-particles in succession. The group of the periodic table to which the resulting daughter element would belong to

  • Group 14

  • Group 16

  • Group 4

  • Group 6


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9.

The absolute enthalpy of neutralisation of the reaction

MgO(s) + 2HCl(aq)  MgCl2(aq) + H2O(l)

will be

  • less than - 57.33 kJ mol-1

  • - 57.33 kJ mol-1

  • greater than-- 57.33 kJ mol-1

  • 57.33 kJ mol-1


10.

Equilibrium constants K1 and K2 for the following equilibria
NO (g) + 12O2  K1 NO2(g) and

2NO2(g) K2 2NO (g) + O2(g)

are related as

  • K2 = 1 K1

  • K2 = K12

  • K2 = K12

  • K2 =1K12


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