A colloidal solution of gold nanoparticles is prepared by reduction of $HAuCl_4$. Which of the following methods is MOST EFFECTIVE for purifying this solution from excess reactants and small ionic byproducts?

Which technique is employed to separate two miscible liquids with a significant difference in their boiling points?

Which method is best suited for separating a mixture of two immiscible liquids with different densities?

Which of the following methods is most suitable for separating a mixture of iodine and potassium chloride?

A mixture of sand, salt, and iron filings can be separated using a combination of methods. Which sequence is the most efficient?

Which of the following methods is NOT suitable for concentrating a protein solution?