Identification of borax

Borax due to the different processing methods have different shapes, drop shape or oval. Drop shape more irregular cone, cone end connection on a rope string; Basin shape under the upper slightly concave, the surface is not flat, it comes with a columnar, granular crystallization, lower semicircle, relatively smooth. Today many for irregular mass goods, all sizes. All are colorless transparent or translucent white; Hyaline luster. For a long time in the air and easily weathered into white powder. The lighter body, qualitative fragile brittle. Odourless, taste slightly salty, before microstrip sweet, slightly cool feeling. Soluble in water, soluble in boiling water and glycerol. To colorless, transparent, pure, light crisp is preferred. Microscopic identification transmission under polarizer: chip in the colorless, the negative swelled. Interference color for yellow Ⅱ class, on the vertical axis plane appear abnormal interference color of blue and brown, not light. Biaxial crystal; Negative light, refractive index: Np = 1. 447年,海里= 1。 469年,Ng = 1。 472; Birefringence: Ng - Np = 0。 025. Chemical identification ( 1) At the beginning of the product of combustion, easy to melt, the constitution expands degeneration is like a sponge, the heating is melted into a transparent glass ball. ( Check the boron salt) ( 2) Take this product aqueous solution, and hydrochloric acid as acid, can make the curcuma paper into palm red; Place dry, color is darker, humid use according to the test solution, namely into green and black. ( Check the boric acid salt) ( 3) Platinum wire, dip in with hydrochloric acid after wetting, take this product powder, in the colorless flame combustion, the flame is bright yellow. ( Check the sodium salt)