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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)
Account for the following : There is large difference between the melting and boiling points of oxygen and sulphur.
Give reasons for the following : Oxygen has less electron gain enthalpy with negative sign than sulphur.
Why is H2O a liquid and H2S a gas?
Why does NH3 form hydrogen bond but PH3 does not?
Why are halogens strong oxidising agents?
Explain why inspite of nearly the same electronegativity, oxygen forms hydrogen bonding while chlorine does not.
Draw the structures of `H_3PO_2`
Give a reason for the following:
Fluorine gives only one oxide but chlorine gives a series of oxides.
Arrange the following in order of the property indicated set.
HF, HCl, HBr, HI - decreasing bond enthalpy.
Which of the following statement is incorrect?
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:
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?
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 radioactive element in group 16 elements.
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:
