Although expensive, platinum is used as a catalyst to break down harmful gases in car exhaust into less harmful gases. Which statement best describes platinum in this use?
a.It is a homogeneous catalyst, so only a small amount is needed even though it exits with the products.
b.It is a heterogeneous catalyst, so only a small amount is needed and it is easily separated from the products.
c.It is a homogeneous catalyst, so although a large amount is needed, it is easily separated from the products.
d.It is a heterogeneous catalyst, so a large amount is needed and it exits with the products.