Salt is less soluble when the temperature decreases. Salt would dissolve quicker in hot water than cold because the molecules in hot water move faster than cold water because of the higher energy, therefore the molecules of hot water move fast, they can more easily break apart the other molecules of a different substance when they come in contact.
Co2 will dissolve in water if water is saturated with Co2 first then it will absorb some of CO2 it appear as less is absorb that was actually the case . this would make it appear as present of CACO3 is in original sample is lower than it will be too low
