The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is .
The value of n, will be
[R=Rydberg constant]
1
2
3
4
The first ionisation enthalpy of boron is less than beryllium because:
Boron has high nuclear charge
The size of boron atom is more than beryllium atom
p-subshell of boron has only one electron
The size cit boron atom is less than beryllium atom
As the temperature is raised from 20°C to 40C, the average kinetic energy of neon atoms changes by a factor:
2
The dipole moment of HBr is 2.60 x 10-30 Cm and the interatomic spacing is 1.41 .The percent ionic character of HBr is:
11.5%
10.1%
8.2%
4.1%
For an electron whose x-positional uncertainity is 1x 10-10 m, the uncertainity in the x-component of the velocity in ms-1 will be of the order of:
106
103
1012
1015
Which of the following statement(s) is/are correct regarding shielding effect?
The magnitude of screening effect do not depends upon the number of inner electrons
The magnitude of effective nuclear charge decreases in a period.
Greater the shielding effect, lower will be the atomic radii
For a given 'orbit' the shielding effect of electron belonging to different subshell decrease in the order s > p > d >f
When NaNO3 is heated in a closed vessel oxygen is liberated and NaNO3 is left behind,
At equilibrium:
addition of NaNO2 favours reverse reaction
addition of NaNO3 favours reverse reaction
increasing temperature favours forward reaction
decreasing temperature favours backward reaction
:
CaO does not react to CO2 to give CaCO3
backward reaction is very low
CO2 formed escapes out
None of the above
C.
CO2 formed escapes out
In the lime kiln the CO2 formed during decomposition of calcium carbonates escape out continuously. Hence the reaction is not a reversible one and proceeds towards completion.
On the other hand if the reaction takes places in a closed container where none of the reactant or product is allowed to escape then the reaction soon reaches the equilibrium state.