any object absorbs heat from anything cooler than it. when you put alcohol on your skin, first, your body will warm the alcohol until it is the same temperature as your skin, and that feels a little cold to you. once warmed up to body temperature, alcohol can evaporate easily and even though the alcohol has evaporated completely off your hand the cool feeling will still linger until that spot on your hand warms back up to the regular temperature.
I2 is a non-polar molecule while NO3- is an ion. Thus, the existing intermolecular forces are –
London dispersion forces and ion-induced dipole forces.