The melting suggest of a substance decreases with increase in presence of impurities in it. The melting suggest of ice decreases from 0 °C come -22 °C on mix salt in the in appropriate proportion. That is why salt is added to do freezing mixtures to keep ice creams frozen.

I desire to ask that expect ice melts in ~ 0 °C and also we room now adding salt to reduced melting allude but now when we have actually lowered the melting suggest the ice will melt more quickly, then what is the objective of mix salt?




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In the old fashioned process, we provided buttermilk sugar and also a little of vanilla. We placed them right into a churn (which is simply a tiny bucket through a mix blade in that so you can hand mix the contents) and then added ice around the churn (outside the churn) to cool that down. And then you mixed and mixed and mixed and mixed. Yet there to be a problem. Together the ice cream melted, the water it developed was in ~ $\pu32°F$ and even though the ice was colder (a advertising freezer is often around $\pu15°F$ (but a house freezer is warmer)) the water retained the churn at approximately (usually above) $\pu32°F$ ($\pu0°C$). And also ice cream (being an "impure" water mixture) is a liquid, no solid, at $\pu32°F$. So, this wouldn"t work. Get in salt. If you added salt come the ice, then the ice would melt well below $\pu32°F$ and be able come cool the churn to the freezing suggest of the ice cream cream mixture (I think its about $\pu25 °F$, but my memory shouldn"t it is in trusted). So, the salt and ice form a salt water mixture which have the right to be well listed below $\pu32°F$, and also so have the right to cool to listed below $\pu32°F$. If you were to include salt come the recipe, climate you"d need to cool it even an ext to acquire it to frozen (although a small salt provides it taste better, imho). So, salt is added to the cooling mixture and (supposedly) not to the recipe"s ingredients. Ns guess ns should point out the you require to think about walking over warm rocks vs wade in speak an customs of water in ~ the very same temperature.

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Which would certainly burn girlfriend faster? There"s no question that your feet would certainly have much more contact through the water than the hard rocks, so her feet would be an ext damaged by the water (water at $180$ or $\pu200 °F$ will burn you). My point is friend actually want the ice to melt into a salt solution, due to the fact that that will better cool the churn - as lengthy as there"s enough salt so the the fluid is cold enough.