dramatically is the key word; but a noticeable drop in temperature occurs when ammonium chloride is dissolved in water and alcohol; it was this mixture that Gabriel Fahrenheit used to reach what he believed was the lowest temperature, which is why 0 degrees Fahrenheit is below the temperature at which water freezes.

Acetone (propanone) in ice water?
I think that is a standard one used in Organic synthesis for keeping reactions cool.

Ice and Salt, too. But not much.

thanks a lot..
in continue to the previous question-are there any two or more substances that if you mix them together the temperature will drop beneath zero?

ice and salt go sub-zero
Apologies for that about ice water and acetone - I meant dry ice (solid CO2) and acetone. Gets to about -78°C [dry ice alone is about that] - so it doesn't actually reduce the temperature, just makes heat transfer more efficient.

So just salt and ice then.

i meant two or more substances that the initial temperature of each is above zero, and if you mix them together the temperature will drop beneath zero?