BS 753:1987 download.Schedule for Density-composition tables for aqueous solutions of sulphuric acid.
1 Scope
BS 753 gives a table that enables the composition of an aqueous solution of sulphuric acid to be determined from its density at temperatures between 10 °C and 40 °C.
Appendix A gives information on the corrections which are necessary when density is determined by a hydrometer complying with BS 7181>.
Appendix B gives information on the choice of BS hydrometers that are suitable for the determination of density of sulphuric acid solutions.
Appendix C gives examples of the use of a BS hydrometer in conjunction with Table 1.
NOTE The titIe of the publications referrel to in thi* xtandard are Iited on the irnude hack cover.
2 Basis of Table 1
Table 1 is based on data obtained from the International Critical Tables. 1928. Vol. 111, page 56, which are still accepted as authoritative.
It should be observed that the table relates to mass, not to apparent mass in air.
3 Application of Table 1
3.1 Determination of D
Table 1 is arranged primarily for ease in determining the strength of an aqueous solution of sulphuric acid of known density. The density of a solution of known strength can, however, be obtained quite readily from the table. Moreover, by the application of small allowances (see Appendix A) Table I can be used to find the strength of solutions of known relative density or the relative density of solutions of known strength. Consider, for example, a solution containing 10 g of H2S01 in 11)0 g of solution, i.e. one for which g = 10. By looking up the value of 1J corresponding to the value g = 10 under any particular temperature in Table 1, the density of the solution at that temperature can be obtained. Thus, for example, the density of the solution ia 1 070 kg/rn3 at 10 DC, 1 066 kg/rn3 at 20°C, etc. Due allowance, based on the density of water at the various temperatures concerned, can then be made to find the corresponding relative densities at the same temperature as the acid.
It should be observed that the percentage composition g of a solution is independent of its temperature. but G. the number of grams of sulphuric acid in 1 U of solution, varies with the temperature of the solution owing to the change in volume of the solution with change in temperature. Hence, the concentration G should always be associated with a particular temperature. For a given value of G applicable at a particular temperature. Table I can be used to obtain the density of the solution at the specified temperature or at any other temperature within the range of the table. The value of G for the solution at temperatures other than the specified one can also be obtained. For example, consider a solution I I.. of which, at 20 °C, contains 200 g of H2S04. In Table 1 the value of D corresponding to G = 200 under 20 °C is 1 123 kg/m1 and the corresponding value of g is 17.8 g. By tracing the value g = 17.8 g through the table, and interpolating where necessary, the density 1J1 at various temperatures of the solution containing 200 g of H.PSO4 in I L of solution at 20 °C can be obtained and also the number of grams of I-12S01 in I lof the solution at various temperatures.
The following are examples of values which may thus be obtained.
3.2 Double entries
Between D = 1 811 kglm’ and I) = 1 846 kg/& two values of g and two of 6 are given against certain values of D. This is necessary because the density of mixtures of sulphuric acid and water attains a maximum value at a concentration of approximately 97 g of sulphuric acid in 100 g of solution. Hence, over a small range on each side of the maximum, there are two possible concentrations for each particular density. Both values are given in Table 1, the values for the less concentrated solution being given in light type and those for the more concentrated solution in bold type.