Answer:
C- 1, 2 and 5
Explanation:
There are many reactions that occur in the world, and one of the more important ones are known as combustion reactions. These reactions always involve the reaction between oxygen and another element/molecule/compound. So automatically, option 2 needs to be correct, so any answer that does not have option 2 in it (B) is incorrect.
Another important factor of combustion reactions is that they give off heat, because they are exothermic reactions, however since there is no indication of energy levels, so the answer in this question cannot be determined through that method.
One important law in all reactions is the conservation of matter, so whatever atoms enter the chemical reaction, have to exit the chemical reaction (no atoms can suddenly appear without having been there originally. For example, if only oxygen and hydrogen enter a reaction, only a product with oxygen and hydrogen can exit the reaction, it is impossible to have a product containing chlorine, if no chlorine was part of the reactants). By this logic, it is impossible to have water (H₂O) as a product, if the reactants are 1 and 2 (Al and O₂), hence option A is incorrect.
The only other option left is option C, and this option is correct because the overall balanced reaction would look like such:
4Al + 3O₂ --> 2Al₂O₃
This reaction obeys the law of conservation of matter, hence, Option C is correct.
