A sample of drinking water was found to be severely contaminated with chloroform `(CHCl_(3))` supposed to be a carcinogen. The level of contamination was 15 ppm (by mass):
(i) express this in percent by mass
(ii) determine the molality of chloroform in the water sample.

Three samples of water A, Band C have the D.O levels of 4 ppm, and 3.8 ppm and 2.1 ppm respectively the most polluted sample of water is

The only electron in the hydrogen atom resides under ordinary conditions on the first orbit. When energy is supplied, the electron moves to higher energy orbit depending on the amount of energy absorbed. When this electron returns to any of the lower orbits, it emits energy. Lyman series is formed when the electron returns to the lowest orbit while Balmer series is formed when the electron returns to second orbit. Similarly, Paschen, Brackett and Pfund series are formed when electron returns to the third, fourth orbits from higher energy orbits respectively (as shown in figure) Maximum number of lines produced when an electron jumps from nth level to ground level is equal to (n(n-1))/(2) . For example, in the case of n = 4, number of lines produced is 6. (4 rarr 3, 4 rarr 2, 4 rarr 1, 3 rarr 2, 3 rarr 1, 2 rarr 1) . When an electron returns from n_(2) to n_(1) state, the number of lines in the spectrum will be equal to ((n_(2) - n_(1))(n_(2)-n_(1) +1))/(2) If the electron comes back from energy level having energy E_(2) to energy level having energy E_(2) then the difference may be expressed in terms of energy of photon as E_(2) - E_(1) = Delta E, lambda = (h c)/(Delta E) . Since h and c are constant, Delta E corresponds to definite energy, thus each transition from one energy level to another will prouce a higher of definite wavelength. THis is actually observed as a line in the spectrum of hydrogen atom. Wave number of the line is given by the formula bar(v) = RZ^(2)((1)/(n_(1)^(2)) - (1)/(n_(2)^(2))) Where R is a Rydberg constant (R = 1.1 xx 10^(7)) (i) First line of a series : it is called .line of logest wavelength. or .line of shortest energy.. (ii) Series limit of last of a series : It is the line of shortest wavelength or line of highest energy. The difference in the wavelength of the 2^(nd) line of Lyman series and last line of Bracket series in a hydrogen sample is

Terrorists often use ammonium nitrate fertilizer as an ingredient in car bombs . When ammonium nitrate explodes, it decomposes to gaseous nitrogen , oxygen and water vapour. The force of the explasion results from the sudden production of a huge volume of hot gas. It has been claimed that NH_(4) NO_3 fertilizer (NH_4)_(2)HPO_4 Analysis of such a disensitized sample of NH_(4) NO_3 showed the mass % nitrogen to be 33.81% NH_4NO_3 on explosion gives

Terrorists often use ammonium nitrate fertilizer as an ingredient in car bombs . When ammonium nitrate explodes, it decomposes to gaseous nitrogen , oxygen and water vapour. The force of the explasion results from the sudden production of a huge volume of hot gas. It has been claimed that NH_(4) NO_3 fertilizer (NH_4)_(2)HPO_4 Analysis of such a disensitized sample of NH_(4) NO_3 showed the mass % nitrogen to be 33.81% An explosive mixture called Amatol contains :