Human red blood cells contain 0.9% sodium chloride as a component of their cytoplasm. What would happen if an IV solution containing 1.5% sodium chloride is introduced into a person?

Red blood cells will shrink because it is a hypertonic solution.

Explanation:

The sodium chloride concentration is higher: 1.5% > 0.9%, so it is a hypertonic solution. If the cells are immersed in a hypertonic medium - which is, a medium with a sodium chloride concentration higher than the concentration inside the cells - the water cells will move out from the cell. In consequence, the cells will lose water and they will shrink.