Science (English Medium) कक्षा ११ - CBSE Question Bank Solutions for Chemistry

Calculate the energy required for the process 

\[\ce{He^+_{(g)} -> He^{2+}_{(g)} + e^-}\]

The ionization energy for the H atom in the ground state is 2.18 ×10^–18 J atom^–1

Lifetimes of the molecules in the excited states are often measured by using pulsed radiation source of duration nearly in the nanosecond range. If the radiation source has a duration of 2 ns and the number of photons emitted during the pulse source is 2.5 × 10¹⁵, calculate the energy of the source.

The longest wavelength doublet absorption transition is observed at 589 and 589.6 nm. Calculate the frequency of each transition and energy difference between two excited states.

If the photon of the wavelength 150 pm strikes an atom and one of its inner bound electrons is ejected out with a velocity of 1.5 × 10⁷ ms^–1, calculate the energy with which it is bound to the nucleus.

If the velocity of the electron in Bohr’s first orbit is 2.19 × 10⁶ ms^-1, calculate the de Broglie wavelength associated with it.

Calculate the volume occupied by 8.8 g of CO₂ at 31.1°C and 1 bar pressure. R = 0.083 bar L K^–1 mol^–1.

According to Bohr’s theory, the angular momentum of an electron in 5th orbit is ______.

For an electron in the second orbit of hydrogen, what is the moment of momentum as per the Bohr's model?

Which of these statements correctly describe the atomic model according to classical electromagnetic theory?

In Bohr model of hydrogen atom, which of the following is quantised?

According to Bohr's model of hydrogen atom, an electron can revolve round a proton indefinitely, if its path is ______.

Explain the terms Inductive and Electromeric effects.

Hydrogen atom has only one electron, so mutual repulsion between electrons is absent. However, in multielectron atoms mutual repulsion between the electrons is significant. How does this affect the energy of an electron in the orbitals of the same principal quantum number in multielectron atoms?

When an electric discharge is passed through hydrogen gas, the hydrogen molecules dissociate to produce excited hydrogen atoms. These excited atoms emit electromagnetic radiation of discrete frequencies which can be given by the general formula

`bar(v) = 109677 1/n_1^2 - 1/n_f^2`

What points of Bohr’s model of an atom can be used to arrive at this formula? Based on these points derive the above formula giving description of each step and each term.

Calculate the energy and frequency of the radiation emitted when an electron jumps from n = 3 to n = 2 in a hydrogen atom.

Why was a change in the Bohr Model of atom required? Due to which important development (s), concept of movement of an electron in an orbit was replaced by, the concept of probability of finding electron in an orbital? What is the name given to the changed model of atom?

Ionisation enthalpies of elements of second period are given below: Ionisation enthalpy/ k cal mol^–1:

520, 899, 801, 1086, 1402, 1314, 1681, 2080.

Match the correct enthalpy with the elements and complete the graph given in figure. Also write symbols of elements with their atomic number

First member of each group of representative elements (i.e., s and p-block elements) shows anomalous behaviour. Illustrate with two examples.

A plot of volume (V) versus temperature (T) for a gas at constant pressure is a straight line passing through the origin. The plots at different values of pressure are shown in Figure. Which of the following order of pressure is correct for this gas?

Under which of the following two conditions applied together, a gas deviates most from the ideal behaviour?

(i) Low pressure

(ii) High pressure

(iii) Low temperature

(iv) High temperature