Home
Class 12
CHEMISTRY
Account for the following: (i) In the ...

Account for the following:
(i) In the series Sc to Zn, the enthalpy of atomisation of zinc is the lowest.
(ii) The `E^0` value for the `Mn^(3+)//Mn^(2+)` couple is much more positive than that for `Cr^(3+)//Cr^(2+)`.

Text Solution

Verified by Experts

(i) In the series Sc to Zn, the enthalpy of atomisation decreases from left to right. Zinc has fully filled 3d sub shell with inter atomic electronic bonding is weakest in Zn. Therefore zinc has lowest enthalpy of atomisation.
(ii) In the electrochemical series, the substance are arranged in the increasing order of reduction potential. The`E^0` for `Mn^(3+)//Mn^(2+)` is more positive than Eo for `Cr^(3+)//Cr^(2+)`, because Mn has greater tendency to get reduced as compared to Cr. This is why Mn is below Cr in electrochemical series.
Promotional Banner

Topper's Solved these Questions

  • D - BLOCK ELEMENTS F - BLOCK ELEMENTS

    OSWAAL PUBLICATION|Exercise TOPIC-1 (D - BLOCK ELEMENTS, THEIR PROPERTIES AND COMPONDS) LONG ANSWER TYPE QUESTIONS - I|20 Videos

  • D - BLOCK ELEMENTS F - BLOCK ELEMENTS

    OSWAAL PUBLICATION|Exercise TOPIC-1 (D - BLOCK ELEMENTS, THEIR PROPERTIES AND COMPONDS)LONG ANSWER TYPE QUESTIONS - II|12 Videos

  • D - BLOCK ELEMENTS F - BLOCK ELEMENTS

    OSWAAL PUBLICATION|Exercise TOPIC - 2 (F - BLOCK ELEMENT , LANTHANOIDS AND ACTINOIDS)(LONG ANSWER TYPES QUESTIONS)|6 Videos

  • CO-ORDINATION COMPOUNDS

    OSWAAL PUBLICATION|Exercise TOPIC-2 (WERNER.S THEORY BONDING IN CO-ORDINATION COMPOUND , VBT, CFT AND IMPORTANCE OF CO-ORDINATION COMPOUNDS) (Very Answer Type Questions)|19 Videos

  • ELECTRO-CHEMISTRY

    OSWAAL PUBLICATION|Exercise Topic - 3 ELECTROLYSIS , LAWS OF ELECTROLYSIS, BATTERIES, FUEL CELLS AND CORROSION (LONG ANSWER TYPE QUESTIONS)|4 Videos

Similar Questions

Explore conceptually related problems

(a) Complete the following equations: (i) Cr_2O_(7)^(2-) + 2OH^(-) to (ii) MnO_(4)^(-) + 4H^(+) + 3e^(-) (b) Account for the following: (i) Zn is not considered as a transitionelement. (ii) Transition metals form a large number of complexes. (iii) The E^(0) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple.

How would you account for the following: (i) The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series. (ii) The E^0 value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple or Fe^(3+)//Fe^(2+) couple.

Account for the following: (i) Transition elements exhibit higher enthalpies of atomisation. (ii) Cr^(2+) is reducing and Mn^(3+) is oxidising when both have d^4 configuration.

Explain why Mn^(2+) is more stable than Mn^(3+) ?

Account for the following : (i) IC l is more reactive than I_(2) . (ii) Fluorine never acts as the central atom in polyatomic interhalogen compounds. (iii) Halogens are strong oxidising agents.

Account for the following : (i) PCl_(5) is more covalent than PCl_(3) . (ii) Iron on reaction with HCl forms FeCl_(2) and not FeCl_(3) . (iii) The two O-O bond lengths is the ozone molecule are equal.

Account for the following : Mg^(+2) is smaller than O-^(2) ion although both have same electronic structure . (ii) Ionisation enthalpy of nitrogen is more than that of oxygen .

How would you account for the following: (i) Among lanthanoids, Ln (III) compounds are predominant. However, occasionally in solutions or in solid compounds, +2 and +4 ions are also obtained. (ii) The E_(M^(2+)//M)^(0) for copper is positive (0.34 V). Copper is the only metal in the first series of transition elements showing this behaviour. (iii) The metallic radii of the third (5d) series of transition metals are nearly the same as those of the corresponding members of the second series.

How would you account for the following: (i) Cr^(2+) is reducing in nature while with the same d-orbital configuration (d^4) Mn^(3+) is an oxidising agent. (ii) In a transition series of metals, the metal which exhibits the greatest number of oxidation state occurs in the middle of the series.

Account for the following : (i) Ammonia is more basic than phosphine. (ii) Elements of Group - 16 generally show lower value of first ionisation enthalpy compared to the elements in the corresponding periods of Group - 15. (iii) Electron pair gain enthalpy with (-)ve sign for fluorine is less than that for chlorine.

OSWAAL PUBLICATION-D - BLOCK ELEMENTS F - BLOCK ELEMENTS -TOPIC-1 (D - BLOCK ELEMENTS, THEIR PROPERTIES AND COMPONDS)(SHORT ANSWER TYPE QUESTIONS - I)
  1. Explain briefly how +2 state becomes more and more stable in the first...

    Text Solution

    |

  2. Name be oxo-metal anions of the first series of the transition metals ...

    Text Solution

    |

  3. What are the characteristics of the transition elements and why are th...

    Text Solution

    |

  4. In what way is the electronic configuration of transition elements dif...

    Text Solution

    |

  5. How is potassium permanganate ( KMnO4) prepared from MnO2 ? write the ...

    Text Solution

    |

  6. Write the structure of MnO4^(2-) and MnO(4)^(-) ions.

    Text Solution

    |

  7. Explain why: (i) E^0 for Mn^(3+)//Mn^(2+) couple is more positive th...

    Text Solution

    |

  8. Complete the following chemical equations: (i) MnO(4)^(-) (aq) + S2O...

    Text Solution

    |

  9. Assign reasons for the following: (i) Copper (I) ion is not known in...

    Text Solution

    |

  10. Assign reasons for each of the following: (i) Transition metals gene...

    Text Solution

    |

  11. How would you account for the following: (i) Cr^(2+) is reducing in ...

    Text Solution

    |

  12. State reasons for the following: (i) Cu(I) ion is not stable in an a...

    Text Solution

    |

  13. Explain giving reasons : (i) Transition metals and their compounds g...

    Text Solution

    |

  14. Account for the following: (i) Cu^(+) ions are not stable in aqueous s...

    Text Solution

    |

  15. How would you account for the following: (i) The atomic radii of the...

    Text Solution

    |

  16. Name the reaction that takes place when a mixture of potassium dichrom...

    Text Solution

    |

  17. Account for the following: (i) In the series Sc to Zn, the enthalpy ...

    Text Solution

    |

  18. Account for the following: (i) Transition elements exhibit higher en...

    Text Solution

    |

  19. Explain the following observations: (i) Generally, there is an incr...

    Text Solution

    |

  20. Explain the following observations: (i) Transition elements generall...

    Text Solution

    |