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
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 ,
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
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
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
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.
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