If we examine the mirror closely, we see it emits a silver light. Some say it is mercury, while others claim it is silver.
In the past, when mirrors were produced, a layer of tin was applied to the back of the glass, followed by pouring mercury over it. Mercury could dissolve tin, creating a white solution with adhesive properties. This “mercury and tin solution” could adhere to the mirror’s surface.
However, producing a mirror this way was labor-intensive, and mercury is toxic, plus the mirror surface was not very bright.
Today, most mirrors are created by applying a layer of silver to the glass. This silver layer generates “the silver and glass reaction.”
You can perform this experiment yourself. First, take a clean test tube and pour in 2 ml of a 2% silver solution. Then, slowly add 5% ammonia until the initial precipitate completely dissolves. Afterward, add 2 ml of a 10% glucose solution. Mix the solution well and place the test tube in hot water at a temperature of 60°C-80°C. After a short while, a shiny layer of silver will appear inside the test tube. You have successfully created the substance to coat the back of the mirror.
Glucose is a reducing agent; it can reduce silver in silver nitrate to metallic silver, which deposits on the glass surface. In addition to using glucose for silver reduction, mirror manufacturing workshops also utilize formaldehyde or tin(II) chloride for this purpose. To ensure the mirror’s durability, after applying the silver layer, an additional coat of red paint is applied to protect the silver layer from peeling off.
