Total Alkalinity and pH of Personal Care Products (page 2)
The lemon juice should have a pH of about 2. The tap water should have a pH of 7. If the pH values you find are widely different, you might have a problem with the cleanliness to your cup. Pure water will measure close to 0 in alkalinity, unless you have very hard water. The water with baking soda will have a much higher alkalinity. Many of the personal care products will have pH values close to 7, which is neutral. Products that are used for cleansing and have some soap in them may be on the basic side, but probably much closer to neutral than normal soap. Many products will have significant alkalinity values.
You measured the pH of the lemon juice and water to make sure you were using the pH paper correctly and to double check that factors like old soap on your glassware weren’t affecting your results. You measured the alkalinity of the water and baking soda solutions for the same reasons. The reason many of the products you tested have a pH close to neutral is because both high and low pH values can irritate skin, especially the eyes. Many of the products contain alkaline materials to absorb any extra acid and keep the product’s pH stable.
Total alkalinity and pH are only two of many factors personal care product designers have to consider. Find about what ingredients are likely to cause allergic reactions and how product safety is tested.
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