which of the following pairs are isostructural?
1. XeF2 , IF2–
2.NH3 , BF3
3.CO3^–2 , SO3^–2
4.PCl3 , ICI5
plzz provide an explaination to the answer
Answers
Answer:
Answer : The correct option is, (1) SO_4^{2-}\text{ and }BF_4^-SO
4
2−
and BF
4
−
Explanation :
Isostructural : It is defined as the species that have the same shape and hybridization.
Now we have to determine the hybridization of the following molecules.
Formula used :
\text{Number of electron pair}=\frac{1}{2}[V+N-C+A]Number of electron pair=
2
1
[V+N−C+A]
where,
V = number of valence electrons present in central atom
N = number of monovalent atoms bonded to central atom
C = charge of cation
A = charge of anion
(1) The given molecules are, SO_4^{2-}\text{ and }BF_4^-SO
4
2−
and BF
4
−
\text{Number of electron pair in }SO_4^{2-}=\frac{1}{2}\times [6+2]=4Number of electron pair in SO
4
2−
=
2
1
×[6+2]=4
The number of electron pair are 4 that means the hybridization will be sp^3sp
3
and the electronic geometry of the molecule will be tetrahedral.
\text{Number of electron pair in }BF_4^-=\frac{1}{2}\times [3+4+1]=4Number of electron pair in BF
4
−
=
2
1
×[3+4+1]=4
The number of electron pair are 4 that means the hybridization will be sp^3sp
3
and the electronic geometry of the molecule will be tetrahedral.
(2) The given molecules are, NH_3\text{ and }NH_4^+NH
3
and NH
4
+
\text{Number of electron pair in }NH_3=\frac{1}{2}\times [5+3]=4Number of electron pair in NH
3
=
2
1
×[5+3]=4
The number of electron pair are 4 that means the hybridization will be sp^3sp
3
and the electronic geometry of the molecule will be tetrahedral.
But as there are 3 atoms around the central nitrogen atom, the fourth position will be occupied by lone pair of electrons. The repulsion between lone and bond pair of electrons is more and hence the molecular geometry will be trigonal planer.
\text{Number of electron pair in }NH_4^+=\frac{1}{2}\times [5+4-1]=4Number of electron pair in NH
4
+
=
2
1
×[5+4−1]=4
The number of electron pair are 4 that means the hybridization will be sp^3sp
3
and the electronic geometry of the molecule will be tetraheadral.
(3) The given molecules are, CO_2\text{ and }CO_3^{2-}CO
2
and CO
3
2−
\text{Number of electron pair in }CO_2=\frac{1}{2}\times [4]=2Number of electron pair in CO
2
=
2
1
×[4]=2
The number of electron pair are 2 that means the hybridization will be spsp and the electronic geometry of the molecule will be linear.
\text{Number of electron pair in }CO_3^{2-}=\frac{1}{2}\times [4+2]=3Number of electron pair in CO
3
2−
=
2
1
×[4+2]=3
The number of electron pair are 3 that means the hybridization will be sp^2sp
2
and the electronic geometry of the molecule will be trigonal planer.
(3) The given molecules are, CH_4\text{ and }BF_3CH
4
and BF
3
\text{Number of electron pair in }CH_4=\frac{1}{2}\times [4+4]=4Number of electron pair in CH
4
=
2
1
×[4+4]=4
The number of electron pair are 4 that means the hybridization will be sp^3sp
3
and the electronic geometry of the molecule will be tetrahedral.
\text{Number of electron pair in }BF_3=\frac{1}{2}\times [3+3]=3Number of electron pair in BF
3
=
2
1
×[3+3]=3
The number of electron pair are 3 that means the hybridization will be sp^2sp
2
and the electronic geometry of the molecule will be trigonal planer.
From this we conclude that, SO_4^{2-}\text{ and }BF_4^-SO
4
2−
and BF
4
−
pairs have the same shape and hybridization. So, these pairs are isostructural.
Hence, the correct option is, (1) SO_4^{2-}\text{ and }BF_4^-SO
4
2−
and BF
4
−