Question

Imagine that you have a barrel of salt, but you forgot to label it. You know it must be either KNO

₃, or KCl.

You look at the solubility curves for KNO₃ and KCl and you find that at 35 degrees Celsius, 100 g of water can dissolve about 30 g of KNO

₃, or about 37 g of KCl.

You have a scale, a hot plate, a thermometer, empty beakers, and plenty of water.

A How can you determine whether the barrel contains KNO₃ or KCl? Hint: What property could you use to identify the mystery salt?

B Explain exactly what you would do and why you would do it.

C How would your results identify the mystery salt? Hint: What results would indicate KNO₃? What results would indicate KCl?

Answer 1

A) We can use the solubility of salts to find if the salt is KCl or KNO3

B) First of all, I will take about 30 grams of the salt and dissolve the salt in the water. Mpw I will take another 5 grams of the salt, and try to dissolve the salt in the water. If the salt dissolves completely in water, the salt is KCl since water dissolves 37 g of KCl per 100g of water. if the salt doesn't dissolves, the salt is KNO3.

C)if any excess salt (more than 30 grams upto 37 grams) dissolves in water, the salt is KCl, else it is KNO3.