Question

what will happen if dry kidney beans are left in pure water for some time

Answer 1

the dry kidney beans will gain water by osmosis

Answer 2

When the dry seed beans is left on the surface of water. The seed coat of the dry seed beans is a hydrophilic substance which imbibe water by the process known as imbibition. Imbibition results in water molecules around the seed coat which then enters the seed by the process known as osmosis. This results in the swelling of the seed. Thus the seeds swell up.