With the rapid increase of the number of cars, solving the environmental problems caused by cars has become a research topic in the automobile industry. The following pictures were collected by Xiao Gang.
(1) methane
(2) mixture; B.C.
(3)①2H 2+O2 2H 2o； ②2B+6H 2 O 2B(OH) 3 +3H 2
(4) Hydrogen fuel