Class 11th

This is a Long Answer Type Questions as classified in NCERT Exemplar

Mendeleev's arranged the elements as the periodicity of their atomic weights.

The drawbacks of Mendeleev's periodic table are as follows:-

(a) The position of hydrogen in the periodic table is not specified

(b) Isotopes are not included in the periodic table

(c) Elements with higher atomic mass are placed before the elements with lower atomic mass. For e.g- Co & Ni

(d) Gaps are left in his table considering the fact that more elements are yet to be discovered

(e) Inappropriate position of group VII.

This is a Long Answer Type Questions as classified in NCERT Exemplar

The group 1 elements are called alkali metals which possess outermost electronic configuration as ns1 .All the elements that have same outermost electron configuration possess similar properties and are placed in the same group.

This is a multiple choice answer as classified in NCERT Exemplar

When the gas is compressed adiabatically, the total work done on the gas increases its internal energy which in turn increases the KE of the gas molecule and hence, the collisions between molecules also increases.

This is a multiple choice answer as classified in NCERT Exemplar

(a), (c) pV=nRT

(a) when pressure p =constant

volume is directly proportional to temperature

(b) when T= constant

from PV =constant

so the graph is rectangular hyperbola

(c) when V =constant

from pressure is directly proportional to temperature.

So the graph is straight the passes through the origin.

PV $\propto T$

PV/T=constant

So the graph hence through origin. So d is correct.

This is a multiple choice answer as classified in NCERT Exemplar

(a), (d) The total energy associated with the molecule is

E= $\frac{1}{2}m{v}_x^2+\frac{1}{2}m{v}_y^2+\frac{1}{2}m{v}_z^2+\frac{1}{2}{I}_x{w}_x^2+\frac{1}{2}{I}_y{w}_y^2$

The number of independent terms in the above expressions is 5. So we can predict velocities of molecule by maxwell's distribution, hence the above expression obeys maxwell 's distribution .

So 2 rotational and 3 translational energies are associated with each molecule

So rotational energy at a given temperature is 2/3 of the translational KE of each molecule.

This is a multiple choice answer as classified in NCERT Exemplar

(c) According to kinetic theory, we know walls only exert perpendicular forces on molecule. They do not exert parallel force . so there is only change in translational motion.

So pV=2/3E

Where E is representing only translational part of energy.

This is a multiple choice answer as classified in NCERT Exemplar

(b), (d) due to the presence of external positive charge on face ABCD. The usual expression for pressure on the basis of kinetic energy will not be valid as ions would also experience electrostatic force. So presence of positive charge the isotropy is also lost.

This is a multiple choice answer as classified in NCERT Exemplar

(d) pV=nRT

So n= PV/RT

As number moles are fixed

$\frac{P_1{V}_1}{{RT}_1}=\frac{P_1{V}_1}{{RT}_1}$

P₂=p₁V₁ (T₂/V₂T₁)

= $\frac{p\mathrm{V\; (}\left(1.1\mathrm{T)}\right)}{1.05\mathrm{V\; (}\left(\mathrm{T)}\right)}$

= P $*\frac{1.1}{1.05}\approx 1.05P$

This is a multiple choice answer as classified in NCERT Exemplar

(b) For a function f (v), the number of molecules n=f (v) which are having speeds between v and v+dv

So f₁ (v) and f₂ (v) will obey's maxwell distribution law