Table of Contents
Why Distilled Water
In all operations in assaying and chemical analysis it is desirable to use distilled water. There are very few places where the assayer cannot procure distilled water.
How to Purify Water for Laboratory Purposes without Distilling
If it is necessary to use ordinary water, add a few drops of nitrate of silver solution made by dissolving a small piece of chemically pure silver foil in a little chemically pure nitric acid. This wash may be prepared in a large glass bottle. Upon the first addition of the silver nitrate solution to undistilled water a milky cloud will appear in the water, which is silver chloride. Shake the bottle and allow this cloud to settle, then add a few more drops of the silver nitrate solution. If no further milky cloud is produced upon the addition of the silver nitrate solution, all the chlorine in the water has been precipitated as silver chloride. The water may now be decanted off into another stoppered container and is ready for use.
A Convenient Form of Apparatus for Distilling Water
A convenient apparatus for making distilled water may be obtained from most laboratory supply houses. The still illustrated (Fig. 56) has a capacity of about 1000 c.c. per hour.
