Question

why do you think raisins in the jar containing concentrated solution shrink

Answer 1

because it act as hypertonic solution
inside raisen their is low concentrations of water and outside it is high therefore it loses water and shrink

Answer 2

when raisins are put in a jar containing concentrated solution shrinks due to the phenomenon of exosmosis
if the water concentration of the cell of the raisin is higher than the solution , the solution is said to be hypertonic solution. therefore, the raisin will lose water from its cells and hence shrinks so that the water concentrated solution will be equal.

hope it helps!:)