The correct set of quantum numbers for the unpaired electron of a chlorine atom is :
2 , 0 , 0 , +
2 , 1 , -1 , +
3 , 1 , -1 ,
3 , 0 , 0 ,
C.
3 , 1 , -1 ,
17Cl = 1s2 2s2 2p6 3s2 3p5
One unpaired electron is present in 3p orbital
3p
r = 3 m = -1
l = 1 s =
A 25 W bulb emits monochromatic yellow light of wavelength of 0.57 m. Calculate the rate of emission of quanta per second.
7.169 x 1019
4.569 x 1019
8.579 x 1019
9.662 x 1019
A.
7.169 x 1019
25 watt = 25 Js-1
E = NHv =
25 =
N = 7.169 x 1019 quanta s-1
When 2.495 g of CuSO4 · x H2O (molar mass 249.5) is heated, 0.05 mole of H2O is lost. Therefore , x is :
one
three
five
seven
C.
five
Number of moles of CuSO4 . xH2O = = 0.01 mole
Moles of H2O = 0.01 x mole
= 0.05 mole
x = 5
Each NH3 molecule has six other NH3 molecules as nearest neighbours in solid state ; H of sublimation of NH3 molecule at the m.p. is 30.8 kJ mol-1 and in the absence of H-bonding estimated Ml of sublimation is 14.4 kJ mol-1 .Hence , strength of H-bond in solid NH3 is :
5.47 kJ mol-1
10.93 kJ mol-1
16.40 kJ mol-1
- 16.40 kJ mol-1
A.
5.47 kJ mol-1
Total strength of all H-bonds :
= 30.8- 14.4
= 16.4kJ mol-1
There are six nearest neighbours, but each hydrogen bond involves 2 molecules. Hence, effective neighbours = 3.
Hence , strength of H-bond ;
= = 5.47 KJ mol-1.
Which of the following compounds is the weakest Bronsted base ?
C.
Compounds and
both have a stronger tendency to accept a proton and hence are stronger Bronsted bases than phenol (c) and alcohol (d). Since, phenol is more acitive than alcohol , therefore, phenol has the least tendency to accept a proton and hence it is the weakest Bronsted base.
Which one ofthe following is not tetrahedral in shape ?
SiCl4
N
CH4
SF4
D.
SF4
SF4 has trigonal bipyramid geometry since it has sp3d hybridisation.
When 6 g of a monobasic acid is dissolved in 100 mL solution , it is l N. What is equivalent mass of the acid ?
20 g equiv-1
40 g equiv-1
60 g equiv-1
80 g equiv-1
C.
60 g equiv-1
From w =
E = =
= 60 g equiv-1
N2O is isoelectronic to CO2 and . Which of the following is the structure of N2O ?
N-O-N
N-N-O
C.
N-N-O
N2O is isoelectronic with CO2 and N3. Hence, its structure is linear i.e. , N=N ➔ 0.
Calculate the radius of a water molecule assuming to be spherical (density= 1 g mL-1) :
1.925 10-8 cm
1.925x 10-9 cm
1.925 10-10 cm
1.925 10-11 cm
A.
1.925 10-8 cm
Mass of one molecule = g
Volume of one molecule =
= 3.0 x 10-23
= 3.0 x 10-23
r3 =
r = = 1.925 x 10-8 cm
Number of lone pair in XeOF4 is :
zero
one
two
three
B.
one
Number of lone pair in XeOF4 is one ,
XeOF4 (sp3d2 hybridisation)