Debunking the Mystery: Is Water Glass a Pure Substance or a Mixture?

Water glass, commonly known as sodium silicate, is a mixture when referred to in its typical form. Here's the breakdown:

Chemical Definition: Sodium silicate (Na₂SiO₃) itself is a compound and would qualify as a pure substance if isolated in solid form.

Practical Usage: However, "water glass" usually refers to the aqueous solution of sodium silicate dissolved in water. This solution is a homogeneous mixture because it contains two components (sodium silicate and water) physically combined without chemical bonding.

Thus, in most contexts (e.g., industrial or commercial applications like adhesives or sealants), water glass is a mixture. If discussing pure solid sodium silicate, it would be a pure substance, but this is less commonly implied by the term "water glass."

Final Answer: Water glass is a mixture (a solution of sodium silicate in water).