If you have a bowl of ice that's melting, so the ambient temperature is just above 0 °C, what happens to the temperature of the water when you add salt?
I know that the freezing point of salt water is less than 0 °C (it goes down to around -21 °C for a fully saturated solution), but that's not what this question is about. There's no change in the ambient temperature.
Does adding the salt create a reaction that adds or removes heat? or does the temperature just remain the same?