Calculate the molality of 1 litre solution of 93% H₂SO₄ (weight/volume). The density of the solution is 1.84 g/ml

A mixture of H₂C₂O₄ (oxalic acid) and NaHC₂O₄ weighing 2.02 g was dissolved in water and solution made upto one litre. Ten millilitres of the solution required 3.0 ml. of 0.1 N sodium hydroxide solution for complete neutralization. In another experiment, 10.0 ml. of the same solution, in hot dilute sulphuric acid medium. require 4.0 ml. of 0.1 N potassium permanganate solution for complete reaction. Calculate the amount of H₂C₂O₄ and NaHC₂O₄ in the mixture.

According to Bohr's theory, the electronic energy of hydrogen atom in the n^th Bohr's orbit is given by $${E_n} = {{ - 21.6 \times {{10}^{ - 19}}} \over {{n^2}}}J$$. Calculate the longest wavelength of light (in Å) that will be needed to remove an electron from the third Bohr orbit of the He⁺ ion.

Amongst the following elements (whose electronic configuration are given below), the one having the highest ionization energy is: