CO is isoelectronic with
(a) NO+
(b) N2
(c) SnCl2
(d) N02
(a, b) Number of electrons in CO =14
Number of electrons in NO+ =14
Number of electrons in N2 = 14
Number of electrons in SnCl2 = 84
Number of electrons in N0–2 = 24
Assertion (A): Though the central atom of both NH3 and H20 molecules are sp3 hybridised, yet H – N – H bond angle is greater than that of H – O – H.
Reason (R): This is because nitrogen atom has one lone pair and oxygen atom has two lone pairs.
(a) A and R both are correct, and R is the correct explanation of A.
(b) A and R both are correct, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A and R both are false.
(a) How many a and n bonds are present in
(b) Why Hf is more stable than H2?
(c) Why is B2 molecule paramagnetic?
Write the important conditions required for the linear combination of atomic orbitals to form molecular orbitals.
Explain the diamagnetic behaviour of P2 molecule on the basis of molecular orbital theory.
Predict the shapes of the following molecules on the basis of hybridization. BC13, ch4, co2, nh3
In which of the following molecule/ion all the bonds are not equal?
(a) XeF4
(b) BF–4
(c) C2H4
(d) SiF4
Which of the following statements are not correct?
(a) NaCl being an ionic compound is a good conductor of electricity in the solid state.
(b) In canonical structures there is a difference in the arrangement of atoms.
(c) Hybrid orbitals form stronger bonds than pure orbitals.
(d) VSEPR theory can explain the square planar geometry of XeF4.
Out of bonding and antibonding molecular orbitals, which one has lower energy and which one has higher stability?
In PO43- ion the formal charge on the oxygen atom of P – O bond is
(a) +1 (b) -1 (c) -0.75 (d) +0.75
Which molecule/ion out of the following does not contain unpaired electrons?
(a) N+2
(b) 02
(c) O22-
(d) B2
Using molecular orbital theory, compare the bond energy and magnetic character of 0+2 and O–2
Match the items given in Column I with examples given in Column II.
| Column I | Column II |
| (i) Hydrogen bond | (a) C |
| (ii) Resonance | (b) LiF |
| (iii) Ionic solid | (c) H2 |
| (iv) Covalent solid | (d) HF |
| (e) 03 |
Use Lewis symbols to show electron transfer between the following atoms to form cations and anions (a) K and S (b) Ca and O (c) Al and N.
What is an ionic bond? With two suitable examples explain the difference between an ionic and covalent bond?
Match the species in Column I with the type of hybrid orbitals in Column II.
| Column I | Column II |
| (i) SF4 | (a) sp3cf |
| (ii) if5 | (b) d2sp3 |
| (iii) NO2+ | (c) sp3 d |
| (iv) NH4 | (d) sp3 |
| (e) sp |
Assertion (A): Among the two O – H bonds in H20 molecule, the energy required to break the first O – H bond and other O – H bond is the same.
Reason (R): This is because the electronic environment around oxygen is the same even after breakage of one O – H bond.
(a) A and R both are correct, and R is the correct explanation of A.
(b) A and R both are correct, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A and R both are false.
Write Lewis symbols for the following atoms and ions: S and S2– ; Al and Al3+; H and H–
Draw the Lewis structures for the following molecules and ions:
H2S, SiCl4 , BeF2, C032-, HCOOH
Discuss the shape of the following molecules using the VSEPR model:
BeCl2, BCl3 , SiCl4, AsF5, H2S, PH3
3PO3 can be represented by structures 1 and 2 shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing H3PO3? If not, give reasons for the same.
Although both CO2 and H2O are triatomic molecules, the shape of H2O molecule is bent while that of CO2 is linear. Explain this on the basis of dipole moment.
Arrange the following bonds ‘in order of increasing ionic character giving reason.
N-H, F-H, C-H and O-H
Explain why CO2-3 ion cannot be represented by a single Lewis structure. How can it be best represented?
What is meant by the term average bond enthalpy? Why there is difference in bond enthalpy of O – H bond in ethanol (C2H5OH) and water?
Match the species in Column I with the geometry/shape in Column II.
| Column I | Column II |
| (i) H30+ | (a) Linear |
| (ii) HC = CH | (b) Angular |
| (iii) Cl0–2 | (c) Tetrahedral |
| (iv) NH+4 | (d) Trigonal bipyramidal |
| – | (e) Pyramidal |
Match the shape of molecules in Column I with the type of hybridization in Column II.
| Column I | Column II |
| (i) Tetrahedral | (a) sp2 |
| (ii) Trigonal | (b) sp |
| (iii) Linear | (c) sp3 |
Arrange the bonds in order of increasing ionic character in the molecules: LiF, K2O, N2, SO2 and ClF3.
Is there any change in the hybridisation ofB and N atoms as a result of the following reaction ? BF3 + NH3 ——-> F3 B.NH3
Considering X-axis as the intemuclear axis which out of the following will not form a sigma bond and why? (a) Is and Is (b) Is and 2px (c) 2py and 2py (d) Is and 2s
