The substance which reduces the rate of reaction is

Correct option is A

An inhibitor is a substance that decreases the rate of a chemical reaction. Unlike catalysts, which increase the reaction rate without being consumed, inhibitors slow down the reaction or prevent it from occurring by interfering with the reactants or the reaction mechanism. They are widely used in industrial processes, corrosion prevention, and biological systems.
Explanation:
An inhibitor functions by various mechanisms, such as binding to reactants or forming a barrier that impedes the reaction. For example, inhibitors can reduce the activity of enzymes in biochemical reactions or slow oxidation in metals. Importantly, inhibitors are selective and do not completely halt the reaction unless used in large concentrations.
Information Booster:
1. Inhibitors are crucial in preserving the shelf life of food and pharmaceuticals.
2. Common inhibitors in biological systems include enzyme inhibitors, which regulate metabolic pathways.
3. Industrial inhibitors, like corrosion inhibitors, are used to protect metals.
Additional Knowledge:
Catalyst: Catalysts increase reaction rates by lowering the activation energy without being consumed. For example, platinum catalyzes the hydrogenation process.
Collision frequency: Collision frequency refers to the number of molecular collisions per second. While it influences the reaction rate, it does not inherently reduce or increase it. Its role is dependent on energy and orientation.