pBlock ElementsII - Result Question 156
####44. Based on the compounds of group 15 elements, the correct statement(s) is (are)
(2018 Adv.)
(a) $Bi _2 O _5$ is more basic than $N _2 O _5$
(b) $NF _3$ is more covalent than $BiF _3$
(c) $PH _3$ boils at lower temperature than $NH _3$
(d) The $N-N$ single bond is stronger than the $P-P$ single bond
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Solution:
- Statement wise explanation is
(i) Statement (a) $Bi _2 O _5$ is a metallic oxide while $N _2 O _5$ is a non-metallic oxide.
Metallic oxides being ionic are basic in nature while non metallic oxides being covalent are acidic in nature. This confirms more basic nature of $Bi _2 O _5$ in comparison to $N _2 O _5$. Hence, this is a correct statement.
(ii) Statement (b) The electronegativity difference between N(3) and $F(4)$ is less as compared to the electronegativity difference between $Bi(1.7)$ and $F(4)$. More electronegativity difference leads to ionic compounds. Thus, $NF _3$ must be more covalent in nature as compared to $BiF _3$. Hence, this statement is also correct.
(iii) Statement (c) In $NH _3$ intermolecular hydrogen bonding is present, which is altogether absent in $PH _3$. Thus, $PH _3$ boils at lower temperature than $NH _3$. Hence, this is also a correct statement
(iv) Statement (d) Due to smaller size of $N$ the lone pair-lone pair repulsion is more in $N-N$ single bond as compared to $O-P$ single bond. This results to weaker $N-N$ single bond as compared to $P-P$ single bond. Hence, this statement is incorrect.
