The decreasing order of dipole moment of `SO_(2) gt NH_(3) gt AsH_(3) gt BF_(3) gt CO_(2)(mu =0)` What can be concluded about the shapes of the molecules ?
(b) What is the value of `ID` in `SI` unic
(c ) The dipole moment of `HBr` is `2.60 xx 10^(30)Cm` and the interatomic spacing is `1.41 A` What is the percentage of ionic character of `HBr` ? .

Explanation

(i) `SO_(2) implies Bent`
(ii) `NH_(3) implies` Pyramidal
(iii) `AsH_(3)implies` Pyramidal (iv) `BF_(3) implies` Planar
(v) `CO_(2)implies` Linear `(mu =0)`
`EN` of `OgtS` or `C` Eash `S -O` and `C-O` bond should be polar with a-ve charge on the O-atom Since `CO_(2)` has no net dipole moment the two `C-O` bond moment must exactly cancel This can occur only if the two bonds are in a straight line linear The existence of dipole moment in `SO_(2)` suggests that molecukle is bent `NH_(3)` and `AsH_(3)` are both pyramidal but `BF_(3)` is planar From the dipole moments alone, nothing can be concluded about the relative flatnes of the `NH_(3)` and `AsH_(3)` pyramids because the `EN'` s of `N` and As are different
(b) `ID = (10^(-18) esu cm)` and `IC =2.999 xx 10^(9)` esu
`ID = (10^(-18) esu cm) ((IC)/(2.998 xx 10^(9) esu))((1m)/(10^(2)cm))=3.336 xx 10^(-30) Cm`
(c ) % ionic character ` = (mu_(obs))/(mu_(cal))`
`=(2.60 xx 10^(-30) Cm)/((1.60 xx 10^(-19)C) (1.41 xx 10^9-10m))`
`=(2.60 xx 10^(-30) Cm)/(2.26 xx 10^(-29)Cm) = 11.5%`

.