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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
Account for the following: Oxygen shows catenation behavior less than sulphur.
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)
Account for the following : There is large difference between the melting and boiling points of oxygen and sulphur.
List the important sources of sulphur.
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].
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).
Why are halogens strong oxidising agents?
Arrange the following in the order of the property indicated against set :
H2O, H2S, H2Se, H2Te − increasing acidic character.
The boiling points of hydrides of group 16 are in the order:
Match the items of Columns I and II and mark the correct option.
| Column I | Column II |
| (A) \[\ce{H2SO4}\] | (1) Highest electron gain enthalpy |
| (B) \[\ce{CCl3NO2}\] | (2) Chalcogen |
| (C) \[\ce{Cl2}\] | (3) Tear gas |
| (D) Sulphur | (4) Storage batteries |
Given below are two statements labelled as Assertion (A) and Reason (R).
Assertion (A): Electron gain enthalpy of oxygen is less than that of Flourine but greater than Nitrogen.
Reason (R): Ionisation enthalpies of the elements follow the order Nitrogen > Oxygen > Fluorine.
Select the most appropriate answer from the options given below:
Write a balanced chemical equation for the reaction showing catalytic oxidation of NH3 by atmospheric oxygen.
The correct order of ΔiHs among the following elements is
Which of the following compound is a peroxide?
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)
______ 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:
