One Mark Questions
Q 1.Define polarizing power and polalrisability.
Ans . The ability of an atom to deform the electron cloud of an atom is called polarizing power .
while the ease with which any atom can be polarized by its neighbouring bonded atom is called
polarizability.
Q 2.Why PCl5 is more covalent than PCl3 ?
Ans . Because P
5+
has more polarising power than P
3+
.
Q 3.Draw Resonating structure of O3.
Q 4.Why is SF4 more reactive than SF6 ?
Ans . SF4 has two unpaired electrons which it can donate further to extend its valency , hence it is
reactive .’S’ in SF6 has maximum 6 0.S.
Q 5.Explain the following order of bond angle.
NO2
+
> NO2 > NO2
—
Ans. This is because NO2
+
has no lone pair of e-, and hence its linear.NO2 has one unshared e- while
NO2 has one unshared e- pair.Greater the repulsion on N-O bond in case of NO2
-than in case of NO2.
Q6.Suggest the expected shape of the following molecules with reasons.
a.SO2
b.NH3
Ans.(a) In SO2 molecule there are three electron pairs .the three electron pairs should acquire
trigonal planar arrangement with bond angle 120 ° .Since one of the position is occupied by lone pair
the geometry is described as V-shaped or bent shaped.
(b) In NH3 molecule there are are four electron pairs (three bond pairs and one lone pair) .These
four electron pairs adopt tetrahedral geometry but due to the repulsion by lone pair the bond
decreases to 107
0
from 109.5
0
and hence the geometry of ammonia is regarded as pryamidal.
Q 7. Why is CO2 a linear molecule while SO2 a non-linear molecule?
Ans. In SO2 molecule there are two bond pairs and one lone pair of electron .Due to repulsion by
lone pair its bond angle decreases from 120° to 119.5° hence it is not linear whereas in CO
2 molecule
there is no lone pair of electron due to which it has linear geometry.
Q8. i) Calculate formal charges of the atoms in nitrite ion.
Ans. i) Formal charge = V-L- ½ S
V--Total no. of valence electrons in free atom
L-- Total no.of non-bonding electrons
S-- ½ Total no. of bonding electrons
For N= 5 – 2 – ½ 6 = 5 – 3= 0
For O= 6 – 4 – ½ 4 = 2 – 2 = 0
For O(-vely charged)= 6 – 6 – 1/2 x 2 = -1
Total charge = -1
Q 1.Define polarizing power and polalrisability.
Ans . The ability of an atom to deform the electron cloud of an atom is called polarizing power .
while the ease with which any atom can be polarized by its neighbouring bonded atom is called
polarizability.
Q 2.Why PCl5 is more covalent than PCl3 ?
Ans . Because P
5+
has more polarising power than P
3+
.
Q 3.Draw Resonating structure of O3.
Q 4.Why is SF4 more reactive than SF6 ?
Ans . SF4 has two unpaired electrons which it can donate further to extend its valency , hence it is
reactive .’S’ in SF6 has maximum 6 0.S.
Q 5.Explain the following order of bond angle.
NO2
+
> NO2 > NO2
—
Ans. This is because NO2
+
has no lone pair of e-, and hence its linear.NO2 has one unshared e- while
NO2 has one unshared e- pair.Greater the repulsion on N-O bond in case of NO2
-than in case of NO2.
Q6.Suggest the expected shape of the following molecules with reasons.
a.SO2
b.NH3
Ans.(a) In SO2 molecule there are three electron pairs .the three electron pairs should acquire
trigonal planar arrangement with bond angle 120 ° .Since one of the position is occupied by lone pair
the geometry is described as V-shaped or bent shaped.
(b) In NH3 molecule there are are four electron pairs (three bond pairs and one lone pair) .These
four electron pairs adopt tetrahedral geometry but due to the repulsion by lone pair the bond
decreases to 107
0
from 109.5
0
and hence the geometry of ammonia is regarded as pryamidal.
Q 7. Why is CO2 a linear molecule while SO2 a non-linear molecule?
Ans. In SO2 molecule there are two bond pairs and one lone pair of electron .Due to repulsion by
lone pair its bond angle decreases from 120° to 119.5° hence it is not linear whereas in CO
2 molecule
there is no lone pair of electron due to which it has linear geometry.
Q8. i) Calculate formal charges of the atoms in nitrite ion.
Ans. i) Formal charge = V-L- ½ S
V--Total no. of valence electrons in free atom
L-- Total no.of non-bonding electrons
S-- ½ Total no. of bonding electrons
For N= 5 – 2 – ½ 6 = 5 – 3= 0
For O= 6 – 4 – ½ 4 = 2 – 2 = 0
For O(-vely charged)= 6 – 6 – 1/2 x 2 = -1
Total charge = -1
No comments:
Post a Comment