Question

What happens when universal indicator is added to saliva before and after meals

Answer 1

The average value of the pH of saliva is 7.4. This value corresponds to the value of the general pH of the body's extracellular fluid (which includes saliva) and the blood.

This value of 7.4 is weakly basic(just above neutral) and hence when universal indicator is placed, then the color changes can range from yellow to green to blue, as the normal saliva pH ranges are 6.2-7.9

On the other hand, after meals, the color of universal indicator may range from red to yellow to green depending on the type of food eaten. The red color denotes that there might be shift of saliva pH to acidic. Acidic food and metabolism of carbohydrates by bacteria that releases acids, may be the reason for the pH shift to acidic. However, this effect may last only a short while because the saliva functions to buffer acidic state of the oral cavity and to wash them away in the stomach.

Answer 2

Answer:

I don't know

Explanation:

This won't appear in examination