C60 an allotrope of carbon contains: from Chemistry JEE Year 201

Subject

Chemistry

Class

JEE Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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11.

C60 an allotrope of carbon contains:

  • 18 hexagons and 14 pentagons

  • 20 hexagons and 12 pentagons

  • 12 hexagons and 20 pentagons

  • 16 hexagons and 16 pentagons


B.

20 hexagons and 12 pentagons

In C60 hexagonal, 12 pentagonal

Therefore, C60 is an allotrope of carbon that consists of 20 hexagona and 12 pentagons.


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12.

Excessive release of CO2 into the atmosphere results in

  • depletion of ozone

  • polar vertex

  • formation of smog

  • global warming


13.

Magnesium powder burns in air to give:

  • Mg (NO3)2 and Mg3N2

  • MgO and Mg3N2

  • MgO only

  • MgO and Mg(NO3)2


14.

The number of water molecules not coordinated to copper ion directly in CuSO4.5H2O is

  • 2

  • 3

  • 1

  • 4


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15.

The given plots represent the variation of the concentration of a reactant R with time for two different reactions (i) and (ii). The respective orders of the reactions are

  • 0, 1

  • 0, 2

  • 1, 0

  • 1, 1


16.

the correct order of the oxidation states of nitrogen in NO, N2O, NO2 and N2O3 is

  • NO2 < NO < N2O3 < N2O

  • N2O < N2O3 < NO < NO2

  • N2O < NO < N2O3 < NO2

  • NO2 < N2O3 < NO < N2O


17.

Match the catalysts (colum I) with products (column II).
Catalyst - Column I Products - Column II
A. V2O5 (i) Polyethylene
B. TiCl4/ Al(Me)3 (ii) Ethanal
C. PdCl2 (iii) H2SO4
D. Iron oxide (iv) NH3

  • A - iii; B - i; C - ii; D - iv

  • A - ii; B - iii; C - i; D - iv

  • A - iv; B - iii; C - ii; D - i

  • A - iii; B - iv; C - i; D - ii


18.

The aerosol is a kind of colloid in which:

  • Solid is dispersed in gas

  • liquid is dispersed in water

  • gas is dispersed in liquid

  • gas is dispersed in solid


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19.

Consider the van der walls constants, a and b, for the following gases
Gas Ar Ne Kr Xe
a/ (atm dm6 mol-2) 1.3 0.2 5.1 4.1
b/ (10-2 dm3 mol-1) 3.2 1.7 1.0 5.0

Which gas is expected to have the highest critical temperature?

  • Kr

  • Ar

  • Ne

  • Xe


20.

The ore that contains the metal in the form of fluoride is

  • cryolite

  • malachite

  • magnetite

  • Sphalerite


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