Chemistry NCERT Exemplar Solutions Class 12th Chapter Two

A gaseous mixture of two substances A and B, under a total pressure of 0.8 atm is in equilibrium with an ideal solution. The mole fraction of substance A is 0.5 in the vapour phase and 0.2 in the liquid phase. The vapour pressure of pure liquid A is_________atm. (Nearest integer)

If the wavelength for an electron emitted from H-atom is 3.3 * 10^-10m, then energy adsorbed by the electron in its ground state compared to minimum energy required for its escape from the atom, is ___________times. (Nearest integer)

[Given: h = 6.626 * 10^-34 Js]

Mass of electron = 9.1 * 10^-31 kg

At $300\mathrm{K}$ , the vapour pressure of a solution containing 1 mole of $n$ -hexane and 3 moles of $\mathrm{n}$ -heptane is $550\mathrm{m}\mathrm{m}$ of $\mathrm{H}\mathrm{g}$ . At the same temperature, if one more mole of $\mathrm{n}$ -heptane is added to this solution, the vapour pressure of the solution increases by $10\mathrm{m}\mathrm{m}$ of $\mathrm{H}\mathrm{g}$ . What is the vapour pressure in $\mathrm{m}\mathrm{m}\mathrm{H}\mathrm{g}$ of $n$ -heptane in its pure state ?

The region in the electromagnetic spectrum where the Balmer series lines appear is:

The vapour pressure of two volatile liquid A and B at 25°C are 50 Torr and 100 Torr, respectively. If the liquid mixture contains 0.3 mole fraction of A, then the mole fraction of liquid B in the vapour phase is $\frac{x}{17}.$  The value of x is____________.

If the work function of a metal is 6.63 * 10^-19J, the maximum wavelength of the photon required to remove a photoelectron from the metal is _______nm. (Nearest integer)

[Given h = 6.63 * 10^-34 Js, and c = 3 * 10⁸ ms^-1]

If O₂ gas is bubbled  through water at 303 K, the number of millimoles of O₂ gas that dissolve in 1 litre of water is______________. (Nearest integer)

(Given: Henry's Law constant for O₂ at 303 K is 46.82 k bar and partial pressure of O₂ = 0.920 bar)

(Assume solubility of O₂ in water in too small, nearly negligible)

The osmotic pressure of a solution of $\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$ is $0.10\mathrm{a}\mathrm{t}\mathrm{m}$ and that of a glucose solution is $0.20\mathrm{a}\mathrm{t}\mathrm{m}$ . The osmotic pressure of a solution formed by mixing $1\mathrm{L}$ of the sodium chloride solution with $2\mathrm{L}$ of the glucose solution is $\mathrm{x}*{10}^{-3}\mathrm{a}\mathrm{t}\mathrm{m}.\mathrm{x}$ is (nearest integer)(Solutions)

A $100\mathrm{m}\mathrm{L}$ solution was made by adding $1.43\mathrm{g}$ of ${\mathrm{N}\mathrm{a}}_2{\mathrm{C}\mathrm{O}}_3\cdot {\mathrm{x}\mathrm{H}}_2\mathrm{O}$ . The normality of the solution is $0.1\mathrm{N}$ . The value of $x$ is (The atomic mass of $\mathrm{N}\mathrm{a}$ is $23\mathrm{g}/\mathrm{m}\mathrm{o}\mathrm{l}$ )

The shortest wavelength of $\mathrm{H}$ atom in the Lyman series is ${\lambda }_1$ . The longest wavelength in the Balmer Series of ${\mathrm{H}}^{+}$ is: