When preparing home-made ice cream, salt is added to the ice-water mixture. What is its function and why does it work?
If you type your question in google search engine you will find your answer.
Which link should I choose?
Choose the link which you find most appropriate, so which one makes sense. There sould be one called enotes for science.
When preparing homemade ice cream, salt is added to the ice-water mixture for a specific purpose: to lower the freezing point of the ice and create a colder environment. This, in turn, allows for the rapid freezing of the ice cream mixture.
To understand why it works, we need to delve into a concept called freezing point depression. The freezing point of water is typically 0 degrees Celsius (32 degrees Fahrenheit). However, when you add salt to water, it disrupts the formation of ice crystals and lowers the freezing point of the mixture.
The reason salt lowers the freezing point is due to a process called osmosis. Osmosis is the movement of solvent molecules, in this case, water, across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration, in order to equalize the concentrations on both sides.
When salt is dissolved in water, it forms ions (sodium and chloride ions, specifically) that disrupt the water molecules and make it harder for them to form ice crystals. This means that the molecules of the ice cream mixture will require even colder temperatures (below 0 degrees Celsius) to freeze.
As a result, when you add salt to the ice-water mixture, it creates an environment with a much lower freezing point than pure water would have. The ice-water bath becomes even colder than 0 degrees Celsius, which is necessary to freeze the ice cream mixture more effectively and quickly.
By using salt to lower the freezing point, the ice cream mixture freezes faster, preventing large ice crystals from forming. This creates a smoother and creamier texture in the final product.