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CBSE Class 12-science Answered

(i)why m.p in group 15 increases upto arsenic and then decreasesupto bismuth?                              (ii) why fluorine has more hydration energy ?                                                                          (iii) why bond dissociation enthalpy in fluorine is less than that of chlorine?
Asked by sweety | 24 Oct, 2015, 10:44: PM
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Dear sweetsomars3112@gmail.com

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.

In case of multiple questions within a query, please post each question individually and let us know where you are getting stuck so that we would be able to explain things better.

Solution for your first query,
 
(i)The melting points increase down the group due to increase in their atomic size. The unexpected decrease in the melting points of antimony and bismuth is because of their tendency to form three covalent bonds instead of five covalent bonds due to inert pair effect. This results in weakening the attraction among their atoms thus lowering their melting points. Because of larger size of atoms, bismuth has still weaker interatomic forces than antimony and thus has still lower melting point.
 
 
 
 
Regards

Topperlearning Team.
Answered by Prachi Sawant | 25 Oct, 2015, 01:47: PM

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