Calcium carbonate will be formed which is insoluble in water.
The answer is a) K and CrO4 only.
I think it might be C or D
B. The rate of particle collisions increased with a higher temperature.
An <em>inference </em>is a guess that you make <em>based on an observation</em>. You can’t see the particles, so you are guessing (a) that they exist and (b) that the rate of their collisions increases with a higher temperature.
A, C, and D are all incorrect because they are <em>observations</em> that you make.
Catalysts speed up a reaction so it would be the reaction rate increases.
