Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

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11.

Consider the following reversible reaction at equilibrium:

2H2O (g)  2 H2O (g) + O2 (g) ; ΔH = +24.7 KJ

The maximum decomposition of H2O(g) will occur by which of the following change in conditions.

  • Increasing temperature and decreasing pressure

  • Decrease temperature and increasing pressure

  • Increasing both temperature and pressure

  • Increasing temperature at constant pressure


A.

Increasing temperature and decreasing pressure

 Δng = number of moles of gaseous products - number of moles of gaseous reactants

= 3-2 =1

Reaction is endothermic and n > 0, hence, the formation of product will be favoured by increasing the temperature and decreasing the pressure.


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12.

Consider the respective enthalpy for the following reactions:

(I) NH3(g) + 3Cl2 (g)  NCl3 (g) + 3HCl (g); -ΔH1(II) N2(g)+ 3H2 (g)2NH3 (g); -ΔH2(III) H2 (g) + Cl2 (g) 2HCl (g); ΔH3

The enthalpy of formation of NCl3 (g) in terms of ΔH1 , ΔH2  , ΔH3 is:

  • ΔHf= -ΔH1 +ΔH22 - 32 ΔH3

  • ΔHf= ΔH1 +ΔH22 - 32 ΔH3

  • ΔHf= -ΔH1 - ΔH22 - 32 ΔH3

  • None of the above


13.

Presence of phosphoric acid or glycerine or acetanilide retards the decomposition of H2O.This is an example of:

  • Positive catalysis.

  • Negative catalysis.

  • Auto catalysis.

  • Induced catalysis.


14.

Photochemical smog is due to the presence of:

  • Oxides of sulphur.

  • Oxides of nitrogen.

  • Oxides of carbon.

  • Chlorofluoro carbons.


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15.

For binary hydrides of formula M x n the value of n can be fractional for:

  • salt like hydrides

  • interstitial hydrides

  • covalent hydrides

  • polymeric hydrides


16.

The solubility of carbonates decreases below the magnesium group due to decrease in:

  • Lattice energies of solids

  • inter-ionic attraction

  • hydration energies of cations

  • entropy of solution formation


17.

The least energetic conformation of cyclohexane is:

  • Boat form

  • Half chair form

  • Chair form

  • Twisted form


18.

Which of the following is the electron deficient molecule?

  • PH3

  • SiH4

  • C2H6

  • B2H6


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19.

Predict the product:


20.

The correct statement(s) about the compound is/are

  • The total number of stereoisomes possible for X is 6

  • The total number of diastereomers possible for X is 3

  • If the stereo chemistry about the double bond is X is trans, the number of enantiomers

  • If the stereo chemistry about the double bond in x is, the numberof enantiomers possible to X is 3.


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