Why is deionized water used in the soap making?

Answer 1

The addition of any other species into the water would raise its boiling point. I think typically you want to establish a a known temperature in whatever experiment you're doing. If the water was pure, then it would boil at exactly 100C

Answer 2

In some fields of research and production is extremely important to avoid external contamination (from water, other reagents, environment, etc.): pharmaceutical industry, preparation of vaccines, semiconductors industry, preparation of ultra-pure materials, physical and chemical determination of physical/chemical properties, etc.

Answer 3

Deionized water is used in soap making because it helps to create a more consistent and predictable outcome in the soap formulation. It also prevents impurities and minerals in tap water from interfering with the chemical reactions involved in soap making, resulting in a higher quality product.

Answer 4

Avoiding contamination from the water impurities during experiments and alteration of the results.

Answer 5

Deionized water is an ultrapure water used in laboratories, industry of pharmaceutical drugs, electronic materials industry, etc.