Question

Why does nothing happen to us when we drink water, as our stomach contains $\mathrm{HCl}$and when water is added to concentrated acids, a highly exothermic reaction takes place?

Answer 1

Hydrochloric acid in stomach:

• The hydrochloric acid present in the stomach is diluted as compared to the concentrated hydrochloric acid solution.

Addition of water:

• The addition of water in a concentrated solution causes a highly exothermic reaction.
• The addition of water to the dilute dilution does not cause that much effect.
• As here, in Stomach acid is around$200$ times diluted that's why when water is added to it that much high exothermic reaction will not take place.