Question

What are slow and fast reactions? Give examples.

Answer 1

Hint:This question gives the knowledge about the activation energy. Activation energy is the least amount of energy which is needed by the reactants for the formation of products. It is the least amount of energy required to energize or activate the molecules to proceed the reaction.

Complete answer:
The slow reaction is defined as the reaction which takes longer time to complete. The slow reaction possesses a low rate of reaction. They possess higher activation energy. The example of slow reactions are rusting of a water pipe, a piece of newspaper turning yellow and so forth.
The fast reaction is defined as the reaction which takes a shorter time to complete. The fast reaction possesses a high rate of reaction. They possess smaller activation energy. The example of fast reactions are striking a match, burning of petrol in the car engine and so forth.

Additional information:
Activation energy is the least amount of energy which is needed by the reactants for the formation of products. It is the least amount of energy required to energize or activate the molecules to proceed the reaction. The exothermic reactions and endothermic reactions possess different activation energies.
The exothermic reactions are the reactions in which emission of heat energy takes place. This type of reaction generally takes place in rusting of iron, breaking of chemical bonds and so forth.
Characteristics of exothermic reactions are as follows:
1. In exothermic reactions, the energy is generally emitted from the system.
2. In energy profile diagrams of exothermic reactions, the enthalpy of products is lower than the enthalpy of products.
3. The change in enthalpy possesses negative value.
4. The temperature increases as the reaction moves forward.
 The endothermic reactions are the reactions in which absorption of heat energy takes place. This type of reaction generally takes place in melting of ice, in cooking, during photosynthesis and so forth.
Characteristics of endothermic reactions are as follows:
1. In endothermic reactions, the energy is generally absorbed by the system.
2. In energy profile diagrams of endothermic reactions, the enthalpy of products is higher than the enthalpy of products.
3. The change in enthalpy possesses positive value.
4. The temperature decreases as the reaction moves forward.

Note:
The activation energy is the least amount of energy required to energize or activate the molecules to proceed the reaction. Slow reactions experience higher activation energy whereas fast reactions experience lower activation energy.