Mixing Effects

Various effects can happen when mixing substances. These include precipitation of a new substance, evolution of heat, absorption of heat, and evolution of gas (if one of the products is a gaseous substance). Of course, change in the color of the mixture is an apparent indication of a reaction happening. The matter with combination of two or more substances is that toxic chemicals or gases may be the products of the formerly inert substances. In other cases, some chemicals could react vigorously with the production of enormous heat, which in uncontrolled instances can set nearby objects on fire. One of the most hazardous effects of crude mixing of certain substances is that a rapid evolution of toxic fumes may result. Doing such procedure without proper gears and instruments could expose one to hazardous substance.
Reference: 1. D.Crowl and J. Louvar, Chemical Process Safety: Fundamentals with Applications, Prentice Hall (2002) Chapter 2; 2. MSDS sheet from online; 3. http://www.unisa.edu.au/ohsw/procedures/hazard.asp

Management/Process Safety Information and Knowledge/Hazards Management