Adding too much salt is very hard to mask. The best way to fix the problem is to make more soup. You can add cream to thin it out without losing flavor or texture. Otherwise making more soup is the best way to help the soup.
by eating tlas
A carrot will float in salt water because salt water is denser than the carrot. This creates buoyant force that allows the carrot to float. In fresh water, the carrot is denser than the water, causing it to sink.
Carrot cells placed in salt water will lose water due to osmosis, causing them to shrink and become wilted. The high concentration of salt in the water creates a hypertonic environment, leading to water leaving the carrot cells to try to balance the salt concentration.
lemon juice cancels out excess salt. however, there will be lemon flavor. lemon juice cancels out excess salt. however, there will be lemon flavor.
Water moves out of the carrot's cells and into the salt water due the difference in concentration of NaCl. This might account for the spongy-ness of the carrot
If a lot of salt has been added (which I assume is the intention of this question), then the carrot cubes will shrink because the solution will be hypertonic to the carrot cubes. However, adding just the right amount of salt or too little salt can result in the carrot cube staying the same or bloating, respectively.
Water moves out of the carrot's cells and into the salt water due the difference in concentration of NaCl. This might account for the spongy-ness of the carrot
Turgidity will decrease in salt water because water in the carrot will flow out in order to try to equalize the high concentration of salt.
Like the too much salt remedy, try adding a peeled potato to see if it will absorb some of the strong flavor... You can also try adding sugar to counteract the strong onion flavor. Nothing to lose.
there is more water but not in the carrot and it isn't all fresh water but there is more water than salt
This is due to the process of osmosis. The water in the cells of the carrot are trying to reach homeostasis with the salt water, so the water is flowing out of the cells. This results in cells that are limp and that then feel spongy.
Salt draws the water out of the carrot - causing it to be "mushy".