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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
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Give reasons: SO2 is reducing while TeO2 is an oxidising agent.
Give reasons for the following : Oxygen has less electron gain enthalpy with negative sign than sulphur.
Why does NH3 form hydrogen bond but PH3 does not?
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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?
Explain why inspite of nearly the same electronegativity, oxygen forms hydrogen bonding while chlorine does not.
Give reasons Thermal stability decreases from H2O to H2Te.
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Arrange the following in the order of the property indicated against set :
H2O, H2S, H2Se, H2Te − increasing acidic character.
Arrange the following in order of the property indicated set.
HF, HCl, HBr, HI - decreasing bond enthalpy.
Which of the following statement is incorrect?
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:
Which of the following statements are correct?
(i) \[\ce{CaF2 + H2SO4 -> CaSO4 + 2HF}\]
(ii) \[\ce{2HI + H2SO4 -> I2 + SO2 + 2H2O}\]
(iii) \[\ce{Cu + 2H2SO4 -> CuSO4 + SO2 + 2H2O}\]
(iv) \[\ce{Nacl + H2SO4 -> NaHSO4 + HCl}\]
In forming (i) \[\ce{N2 -> N^{+}2}\] and (ii) \[\ce{O2 -> O^{+}2}\]; the electrons respectively are removed from:
Which of the following compound is a peroxide?
