Question

10 cm3 liquid A was mixed with 10 cm3 of liquid B. The volume of the resulting solution was found to be 19.9 cm3. What do you conclude ?

Answer 1

If after adding one liquid to another, the volume is less than the total volume of both the liquids, then it means that there must have been some chemical reaction between the two liquids, because of which some of the part of the liquid either changed to some gas or evaporated.