Favourable conditions for the formation of electrovalent bond is that the cation and anion must have, respectively
high ionisation potential and low electron affinity
low ionisation potential and high electron affinity
high ionisation potential and high electron affinity
low ionisation potential and low electron affinity
Consider the formal charges on N and B in H3N-BF3 and indicate which of the following is true?
N is +ve and B is -ve
N is --ve and B is +ve
both N and B carry similar +ve or -ve charges
charge discrimination is difficult to make
Consider (i) CO2 (ii) CCl4 (iii) C6Cl6 and (iv) CO and tell which of the following statements is correct?
(i), (ii) and (iii) only have zero dipole moment
(i), (ii) and (iv) only have zero dipole moment
only (iv) has zero dipole moment
All have zero dipole moment
Which one of the following represents the correct state of hybridisation of P in PCl5 ?
s0p3
sp3d
s2p3
sp2d2
Aluminium chloride exists as dimer, Al2Cl6, in solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives
Al3+ + 3Cl-
[Al(H2O6]3+ + Cl-
[Al(HO)6]3- + 3HCl
Al2O3 + 6HCl
Which of the following is not true?
In a first order reaction, the half-life is independent to the initial concentration of reactant.
A given piece of charcoal shows increase in its surface area in its powdered form.
In valence bond of H2, each electron spends its time around its own nucleus
In valence bond of H2, both the electrons spend their time around both the nucleus
The correct order of decreasing dipole moment of (I) toluene, (II) m-dichlorobenzene (III) o-dichlorobenzene and (IV) p-dichlorobenzene is
IV < II < I < III
IV < I < II < III
I < IV < II < III
IV < I < III < II
B.
IV < I < II < III
Dipole moment of p-dichlorobenzene is zero, while that of o-dichlorobenzene is 2.54 D and for m-dichlorobenzene is 1.48 D. This shows that benzene ring is planar and in p-C6H4Cl2 two C-Cl bonds are directed in the plane of the ring, thus on adding, they becomes zero. In this, two C-Cl bonds contain an angle of 60° and in m- C6H4Cl2 the two C-Cl bonds contain an angle of 120° and their dipole moments on vector addition give a higher value of dipole moment.
Therefore, sequence of dipole moment is as follows:
p-dichlorobenzene < toulene < m-dichlorobenzene < o-dichlorobenzene