Q8 of 26 Page 1

Why do the transition elements have higher enthalpies of atomization? In 3d series (Sc to Zn), which element has the lowest enthalpy of atomization and why?

The transition elements generally have higher enthalpies of atomisation due to strong metal-metal bonding. The transitions metals have very high effective nuclear charge and due to presence of unpaired electrons, there atomization becomes very difficult. Zn has the lowest enthalpy of atomization as it does not have any unpaired electron.


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6

State Henry’s law. Why do gases always tend to be less soluble when the temperature is raised?

OR


State Raoult’s law for the solution containing volatile compounds. Write two differences between an ideal and a non-ideal solution.


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following reactions occur at cathode during the electrolysis of aqueous sodium chloride solution:

Na+(aq) + e- →Na(s) E° = -2.71V


H+(aq) + e- → H2 (g) E° = 0.00V


(a)On the basis of their standard reduction electrode potential (E°) value, which reaction is feasible at cathode and why?


(b) why does the cell potential of mercury cell remains constant throughout its life?


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(i) write down the IUPAC name of following complex:

[Co(NH3)5(NO2)](NO3)2]


(ii) write down the formula for following complex:


Potassium tetracyanidonickelate(II)


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Name the reagents used in following reactions :

(i)


(ii) CH3-COOH ClCH2COOH