The basis of quantum mechanical model of an atom is
angular momentum of electron
quantum numbers
dual nature of electron
black body radiation
Identify the correct set.
Molecule | Hybridisation of central atom | Shape |
PCl5 | dsp3 | square pyramidal |
[Ni(CN)4]2- | sp3 | tetrahedral |
SF6 | sp3d2 | octahedral |
IF3 | dsp3 | pyramidal |
Which one of the following statements is correct?
Hybrid orbitals do not form σ bonds.
Lateral overlap of p-orbitals or p- and d-orbitals produces -bonds.
The strength of bonds follows the order-
σp-p < σs-s < p-p
s-orbitals do not form σ bonds.
B.
Lateral overlap of p-orbitals or p- and d-orbitals produces -bonds.
Among the given options, option b is the correct one. Others can be corrected as-
a. Hyridised orbitals show only head on overlapping and thus form only σ bonds. They never form bonds.
c. Head on overlapping is stronger than lateral or sideways overlapping. Therefore, the strength of bonds follows the order-
d. s-orbitals are spherically symmetrical and thus show only head on overlapping and form only σ bonds.
The degree of ionization of 0.10 M lactic acid is 4.0%
The value of Kc is
1.66 × 10-5
1.66 × 10-4
1.66 × 10-3
1.66 × 10-2
The pH of a buffer solution made by mixing 25 mL of 0.02 M NH4OH and 25 mL of 0.2 M NH4Cl at 25° is pKb of NH4OH = 4.8)
5.8
8.2
4.8
3.8
For which one of the following reactions, the entropy change is positive?
H2 (g) + O2 (g) → H2O (l)
Na+ (g) + Cl- (g) → NaCl (s)
NaCl (l) → NaCl (s)
H2O (l) → H2O (g)
Solution 'X' contains Na2CO3 and NaHCO3, 20 mL of X when titrated using methyl orange indicator consumed 60 mL of 0.1 M HCl solution. In another experiment, 20 mL of X solution when titrated using phenolphthalein, consumed 20 mL of 0.1 M HCl solution. The concentrations (in mol L-1) of Na2CO3 and NaHCO3 in X are respectively
0.01, 0.02
0.1, 0.1
0.01, 0.01
0.1, 0.01
A compound absorbs light in the wavelength region 490-500 nm. Its complementary colour is
red
blue
orange
blue-green