Reactions can be speeded by increasing the proportion of reactant molecules which collide with proper orientation. This can be accomplished by......... A)compressing the reactant mixture.

B) heating the reactant mixture.
C) addition of a catalyst.
D) cooling the reactant mixture.

The correct answer is B) heating the reactant mixture.

When we increase the temperature of a reactant mixture, the average kinetic energy of the reactant molecules increases. This leads to an overall increase in the speed of the molecules and, as a result, an increase in the frequency of collisions between the reactant molecules.

By increasing the temperature, we also increase the chances of the reactant molecules having enough energy to overcome the activation energy barrier required for a successful reaction. This means that a larger proportion of the reactant molecules will have sufficient energy to react when they collide.

In addition to increasing the frequency and energy of collisions, heating the reactant mixture can also increase the likelihood of the reactant molecules colliding with the proper orientation necessary for the reaction to occur. This is because the increased energy of the molecules allows for greater molecular motion and more favorable collisions.

Therefore, heating the reactant mixture is an effective way to increase the proportion of reactant molecules that collide with the proper orientation, which ultimately speeds up the reaction.