By recrystallization from hot benzene, the a form is obtained in large prisms which melt at 157° C., and at their boiling-point decompose into hydrochloric acid and trichlorbenzene.
The pressure in the refrigerator being reduced by the pump and maintained at such a degree as to give the required boiling-point, which is of course always lower than the temperature outside the coils, heat passes from the substance outside, through the coil surfaces, and is taken up by the entering liquid, which is converted into vapour at the temperature T i.
The colour, the boiling-point, the specific gravity and solubility in alcohol serve as most valuable adjuncts in the examination with a view to form an estimate of the genuineness and value of a sample.
The vaporization of a substance below its normal boiling-point can also be effected by blowing in steam or some other vapour; this operation is termed "distillation with steam."
The relation of the elevation of the boiling-point (t°) to the osmotic pressure (P) is very simply derived from the formula t=o 02407P 0, while the reduction of vapour pressure proportional to the concentration can be very easily obtained from the elevation of the boiling-point, or it may be obtained directly from tables of vapour tension.
- Formerly all chlorate of potash, as some is still, was obtained by passing chlorine into milk of lime, allowing the temperature to rise almost to the boiling-point, and continuing until the bleaching-solution, originally formed, is converted into a mixture of calcium chlorate and chloride, the final reaction being 6Ca(OH)2+6C12=5CaC12+Ca(C103)2+6H20.
The steam rising from the latter is passed into a similar pan, in which it circulates round another set of pipes, but as it could not bring the liquid in the latter to boil under ordinary conditions, the second pan is connected with a vacuum-pump so that the boiling-point of the liquid in this pan is lowered.
Oleum, olive oil), the generic expression for substances belonging to extensive series of bodies of diverse chemical character, all of which have the common physical property of being fluid either at the ordinary temperature or at temperatures below the boiling-point of water.
The graduation of a thermometer is determined by the freezing-point and the boiling-point of water, the interval between these being divided into a certain number of degrees, representing equal increases of temperature.
According to the above formula the critical temperature is given by 8aA/54b, and as the critical temperature is approximately proportional to the boiling-point, both being estimated on the absolute scale of temperature, we may conclude that the larger value of b corresponds to the lower boilingpoint, and indeed the isomer corresponding to the left-hand formula boils at 74°, the other at 114°.