Sodium is preferred over potassium in industrial applications because

a. sodium salts are easily decomposed.
b. potassium has a higher melting temperature.
c. sodium is produced more economically.
d. potassium oxidizes more slowly in air.

pure substance: iron,copper

impure substance: water,charcoal

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".