Which of the following is an example of a double replacement reaction?
(a)3fe + 2o2 fe3o4
(b) bacl2 + k2co3 baco3 + 2kcl
(c) nico3 nio + co2
(d) cl2 + 2nabr 2nacl + br2

15) a substance used in manufacturing gasoline consists of finely divided platinum supported on an inert solid. suppose that the platinum is formed by the high temperature reaction between platinum (iv) oxide and hydrogen gas. the other product is water. a) write and balance the equation b) how many grams of hydrogen are needed to produce 1.0 g of platinum metal? c) how many moles of water are produced at the same time? how many grams? ( show work, .)