Consider the hydrogen atom to be a proton embedded in a cavity of radius a₀ (Bohr radius) whose charge is neutralised by the addition of an electron to the cavity in vacuum, infinitely slowly. Estimate the average total energy of an electron in it's ground state in a hydrogen atom as the work done in the above neutralisation process. Also, if the magnitude of the average kinetic energy is half the magnitude of the average potential energy, find the average potential energy.

A 3.00 g sample containing Fe₃O₄, Fe₂O₃ and an inert impure substance is treated with excess of KI solution in presence of dilute H₂SO₄. The entire iron is converted into Fe²⁺ along with the liberation of iodine. The resulting solution is diluted to 100 ml, A 20 ml of the diluted solution requires 11.0 ml of 0.5 M Na₂S₂O₃ solution to reduce the iodine present. A 50 ml of the diluted solution, after complete extraction of the iodine requires 12.80 ml of 0.25 M KMnO₄ solution in the dilute H₂SO₄ medium for the oxidation of Fe²⁺. Calculate the percentages of Fe₂O₃ and Fe₃O₄ in the original sample.

The orbital angular momentum of an electron in 2s orbital is

Calculate the wave number for the shortest wavelength transition in the Balmer series of atomic hydrogen.

Which of the following has the maximum number of unpaired electrons?

When N₂, the N-N bond distance _____ and when O₂ goes to $$O_2^+$$ the O-O bond distance ___.

The number and type of bonds between two carbon atoms in CaC₂ are:

Among the following species, identity the isostructural pairs NF₃, $$NO_3^-$$, BF₃, H₃O⁺ , HN₃

A mixture of ideal gas is cooled upto liquid helium temperature (4.22K) to form an ideal solution

The following compounds have been arranged in order of their increasing thermal stabilities. Identify the correct order
K₂CO₃ (A), MgCO₃ (B), CaCO₃ (C), BeCO₃ (D)

Explain the difference in the nature of bonding in LiF and LiI.

The molar volume of liquid benzene (density = 0.877 g mL^-1) increases by a factor of 2750 as it vaporises at 20^oC and that of liquid toluene (density = 0.867 g mL^-1) increases by a factor of 7720 at 20^oC. A solution of benzene and toluene at 20^oC has vapour pressure of 46.0 Torr. Find the mole fraction of benzene in the vapour above the solution.

The standard reduction potential for Cu²⁺|Cu is +0.34 V. Calculate the reduction potential at pH = 14 for the above couple. K_sp of Cu(OH)₂ is 1.0 $$\times$$ 10^-19

The ionisation constant of $$NH_4^+$$ in water is 5.6 $$\times$$ 10^-10 at 25^oC. The rate constant for the reaction of $$NH_4^+$$ and $$OH^-$$ to form NH₃ and H₂O at 25^oC is 3.4 $$\times$$ 10¹⁰ L mol^-1s^-1. Calculate the rate constant for proton transfer from water to NH₃.