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प्रश्न
Arrange the following in the order of property indicated for the given set:
F2, Cl2, Br2, I2 - increasing bond dissociation enthalpy.
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उत्तर १
- Bond dissociation enthalpy decreases as the bond distance increases from F2 to I2 due to the increase in the size of the atom on moving from F to I.
- The F-F bond dissociation enthalpy is smaller than the Cl-Cl and even smaller than the Br-Br.
- This is because the F atom is very small and has large electron-electron repulsion among the lone pairs of electrons in F2 molecule where they are much closer to each other than in the case of Cl2.
- The increasing order of bond dissociation enthalpy is:
I, < F2 < Br2 < Cl2
उत्तर २
I2 < F2 < Br2 < Cl2
Due to an increase in atom size, bond dissociation enthalpy reduces as the X-X bond distance in the X2 molecule increases. But F2 is an anomaly since its bond dissociation enthalpy is lower than Br2 and Cl2. This results from the F atom’s extremely small size, as the F-F bond pair in the F2 molecule is repelled by the three lone pairs of electrons on it.
संबंधित प्रश्न
a. Explain the trends in the following properties with reference to group 16:
1 Atomic radii and ionic radii
2 Density
3 ionisation enthalpy
4 Electronegativity
b. In the electolysis of AgNO3 solution 0.7g of Ag is deposited after a certain period of time. Calulate the quantity of electricity required in coulomb. (Molar mass of Ag is 107.9g mol-1)
Give reasons: SO2 is reducing while TeO2 is an oxidising agent.
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The HNH angle value is higher than HPH, HAsH and HSbH angles. Why? [Hint: Can be explained on the basis of sp3 hybridisation in NH3 and only s−p bonding between hydrogen and other elements of the group].
Justify the placement of O, S, Se, Te and Po in the same group of the periodic table in terms of electronic configuration, oxidation state and hydride formation.
Knowing the electron gain enthalpy values for \[\ce{O -> O-}\] and \[\ce{O -> O^{2-}}\] as −141 and 702 kJ mol−1 respectively, how can you account for the formation of a large number of oxides having O2− species and not O−?
(Hint: Consider lattice energy factor in the formation of compounds).
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Arrange the following in the order of the property indicated against set :
H2O, H2S, H2Se, H2Te − increasing acidic character.
Give a reason for the following:
Fluorine gives only one oxide but chlorine gives a series of oxides.
Strong reducing behaviour of \[\ce{H3PO2}\] is due to ______.
Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
These are physical properties of an elements.
- Sublimation enthalpy
- Ionisation enthalpy
- Hydration enthalpy
- Electron gain enthalpy
The total number of above properties that affect the reduction potential is ______. (Integer answer)
What is the basicity of \[\ce{H3PO4}\]?
______ is a radioactive element in group 16 elements.
______ is a gaseous element of group 16.
Given below are two statements:
Statement I: The boiling point of hydrides of Group 16 elements follows the order:
H2O > H2Te > H2Se > H2S
Statement II: On the basis of molecular mass, H2O is expected to have a lower boiling point than the other members of the group but due to the presence of extensive H-bonding in H2O, it has a higher boiling point.
In the light of the above statements, choose the correct answer from the options given below:
