Multiple Choice QuestionsWhich one of the following statements regarding helium is incorrect ?
It is used to fill gas balloons instead of hydrogen because it is lighter and non-inflammable
It is used as a cryogenic agent for carrying out experiments at low temperatures
It is used to produce and sustain powerful superconducting magnets
It is used in gas cooled nuclear reactors
Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species?
Cl <F <S <CO
O <S <F <Cl
S <O <Cl <F
F <Cl <O <S
Sodium thiosulphate is used in photography
as AgBr grain is reduced to non-metallic silve
to convert metallic silver into silver salt
to remove reduced silver
to remove undecomposed AgBr in the form of Na3[Ag(S2O3)2] (a complex salt)
The decreasing order of electron affinity is
I > Br > Cl > F
Br > Cl > F > I
F > Cl > Br > I
Cl > F > Br > I
D.
Cl > F > Br > I
On moving down the group, electron affinity decreases due to increase in size but Cl shows higher electron affinity than fluorine due to vacant d-orbitals.
For the reaction, 2SO2 + O2(excess) → 2SO3 the order of reaction with respect to O2 is
two
three
zero
one
In the manufacture of ammonia by Haber's process, N2 (g) + 3H2(g) 2NH3(g) + 92.3kJ. which of the following conditions is unfavourable?
reducing the temperature
Removing ammonia as it is formed
Increasing the temperature
Increasing the pressure
The key step in the manufacturing of H2SO4 by contact process is
absorption of SO3 in H2SO4 to give oleum
dilution of oleum with water
burning of sulphur in air to generate SO2
catalytic oxidation of SO2 with O2 to give SO3
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