Answer:
Concentration of the reactants decreases;
Rate of a reaction decreases
Explanation:
Since volume is held constant in a solution, the concentration of the reactants will decrease.
Simply speaking, concentration is the ratio between moles and volume. Volume is constant here. Over time, the number of moles of the reactants will decrease, as they react to produce products and they are disappearing. Since moles are directly proportional to concentration, this implies that concentration will also decrease, while the concentration of the products will increase, as they're formed.
The rate of a reaction decreases as the reaction continues, as we have lower and lower amounts of the reactants remaining in the solution as time progresses. Therefore, the probability of a successful collision leading to products decreases.
