An element, X has the following isotopic composition;200X: 90%19

Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Calculate the pOH of a solution at 250C that contains 1 x 10-10 M of hydronium ions.

  • 7

  • 4

  • 9

  • 9


2.

A Weak acid, HA has a Ka of 1.00 x 10-5. If 0.100 mole of this percentage of acid dissociated at equilibrium is closest to:

  • 99.0%

  • 1.00%

  • 99.9 %

  • 99.9 %


3.

Which of the following oxidation states are the most characteristics for lead and tin respectively? 

  • +4,+2

  • +2,+4

  • +4,+4

  • +4,+4


4.

The correct order of C-O bond length among CO, CO32-, CO2 is,

  • CO2<  CO32-<  CO

  • CO <  CO32-<  CO2

  • CO32- <CO2 <CO

  • CO32- <CO2 <CO


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5.

The following equilibrium constants are given:

N2 + 3H2  ⇌ 2NH3; K1

N2 +O2  ⇌ 2NO; K2

H2 + 1/2O2  ⇌ H2O' K3

The equilibrium constants for the oxidation of NH3 by oxygen to give NO is:

  • K2K33 /K1

  • KK2K32 /K1

  • K22K3 /K1

  • K22K3 /K1


6.

Consider the following sets of quantum numbers:


  n l m s
i) 3 0 0 +1/2
ii) 2 2 1 +1/2
iii) 4 3 -2 -1/2
iv) 1 0 -1 -1/2
v) 3 2 3 +1/2

Which of the following sets of quantum number is not possible? 
  • ii, iii and iv

  • i, ii, iii and iv

  • ii, iv and v

  • ii, iv and v


7.

Consider the following reactions:

straight i right parenthesis space straight H to the power of plus space left parenthesis straight g right parenthesis thin space space plus space OH to the power of minus space left parenthesis aq right parenthesis space equals space straight H subscript 2 straight O space left parenthesis straight l right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space increment straight H space equals space minus space straight x subscript 1 space kJ space mol to the power of blank to the power of negative 1 end exponent end exponent
ii right parenthesis space straight H subscript 2 space left parenthesis straight g right parenthesis thin space space plus space straight O subscript 2 space left parenthesis straight q right parenthesis space equals space straight H subscript 2 straight O space left parenthesis straight l right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space increment straight H space equals space minus space straight x subscript 2 space kJ space mol to the power of blank to the power of negative 1 end exponent end exponent
iii right parenthesis space CO subscript 2 space left parenthesis straight g right parenthesis thin space space plus space straight H subscript 2 space left parenthesis straight g right parenthesis space equals space straight H subscript 2 straight O space left parenthesis straight l right parenthesis space plus space CO subscript 2 space left parenthesis straight g right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space increment straight H space equals space minus space straight x subscript 3 space kJ space mol to the power of blank to the power of negative 1 end exponent end exponent
iv right parenthesis straight C subscript 2 straight H subscript 2 space left parenthesis straight g right parenthesis thin space space plus 5 over 2 space straight O subscript 2 space left parenthesis straight g right parenthesis space equals space straight H subscript 2 straight O space left parenthesis straight l right parenthesis space plus 2 CO subscript 2 space left parenthesis straight g right parenthesis
space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space increment straight H space equals space plus space straight x subscript 4 space kJ space mol to the power of blank to the power of negative 1 end exponent end exponent
Enthalpy of formation of H2O (l) is:

  • - x2 kJ mol-1

  • + x3 kJ mol-1

  • - x4 kJ mol-1

  • - x4 kJ mol-1


8.

Given that bond energy of H-H and Cl- Cl are 430 kJ mol-1 and 240 kJ mol-1 respectively and ΔHf for HCl is -90 kJ mol-1. Bond and ΔHf for HCl is -90 kJ mol-1.Bond enthalpy of HCl is:

  • 290 kJ mol-1

  • 380 kJ mol-1

  • 425 kJ mol-1

  • 425 kJ mol-1


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9.

With which of the following electronic configuration an atom has the lowest ionisation enthalpy? 

  • 1s2 2s22p5

  • 1s2 2s22p3

  • 1s2 2s22p5 3s1

  • 1s2 2s22p5 3s1


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10.

An element, X has the following isotopic composition;


200X: 90%

199X : 8.0%

202X ; 2.0 %

The weighted average atomic mass of the naturally -occurring element X is closet to:

  • 200 amu

  • 201 amu

  • 202 amu

  • 202 amu


A.

200 amu

Weight of  200X = 0.90 x 200 = 180.00 amu

Weight of 199X  = 8.08 x 199 = 15.92 amu

Weight 0f  202X =  0.02 x 202 = 4.04 amu

Total weight = 199.06 = 200 amu


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