Answer;
Keep the reactants in separate containers.
Explanation;
-According to the collision theory of reactivity, reactions occur when reactant molecules effectively collide. For an “effective collision” to occur, the reactant molecules must be oriented in space correctly to facilitate the breaking and forming of bonds and the rearrangement of atoms that result in the formation of product molecules.
A, I believe. Because after collecting you need to analyze in order to do many other steps. Also all the other answers are something before collecting data
