26. Q. Why is chlorine a substance of very great commercial importance? A. On account of its extensive use as a bleaching agent.
27. Q. Of what common article is chlorine an important constituent? A. Salt.
28. Q. What are the three most striking properties of chlorine? A. Its noticeable weight—greater than that of the air—its greenish color, and its exceedingly irritating odor.
29. Q. In connection with what two principal properties does chlorine, as a chemical agent, manifest its activities? A. Its affinity for hydrogen and its affinity for the metals.
30. Q. Of what may the substance known as bleaching-powder be spoken in a general way as consisting? A. Of lime saturated with chlorine.
31. Q. When was bromine first recognized as an elementary substance, and by whom discovered? A. In the year 1826, by Balard, a French chemist.
32. Q. Where does the substance bromine occur? A. In the brine of the ocean, and in the water of mineral springs, united with certain metals in the form of bromides.
33. Q. To what does bromine show very decided resemblances, in its chemical relations? A. To chlorine, having affinities for the same substances, only less in intensity.
34. Q. In what processes is bromine an important substance? A. In the processes of photography.
35. Q. In what form has bromine had a very wide and beneficent use, as a remedial agent? A. In the form of potassic bromide.