Final answer:
Hypotonic solution is administered into the cells because it has a lower solute concentration compared to the fluid inside the cells, causing water to move into the cells and potentially leading to cell swelling and lysis.
Step-by-step explanation:
When hypotonic solution is administered, it goes into the cells. This is because a hypotonic solution has a lower solute concentration than the fluid inside the cells, leading to osmosis where water enters the cells to equalize solute concentrations. Excessive water intake can cause cells to swell and potentially lyse (burst), which is why it is important for intravenous (IV) solutions to be isotonic with blood serum to avoid such deleterious effects.