Because plaster of Paris on keeping in container having moisture becomes hard and its volume increases slightly on reaction with water

Introduction:
Plaster of Paris is a white powder made from gypsum, a naturally occurring mineral. It is widely used in various applications such as construction, art and crafts, and medical purposes. Plaster of Paris has the property of setting quickly when mixed with water, which makes it ideal for creating molds and casts. To maintain its effectiveness, it is important to store Plaster of Paris in a moisture-proof container.

Reasons for storing Plaster of Paris in a moisture-proof container:

1. Preservation of chemical properties:
Plaster of Paris is highly susceptible to moisture absorption. When it comes in contact with water, it undergoes a chemical reaction called hydration, converting into gypsum. This reaction leads to the formation of crystalline structures, which increases the volume of the material and weakens its integrity. Storing Plaster of Paris in a moisture-proof container prevents it from absorbing moisture from the surrounding environment, thus preserving its chemical properties.

2. Prevention of premature setting:
The setting process of Plaster of Paris is a result of its chemical reaction with water. If Plaster of Paris is exposed to moisture in the air, it can start setting before it is intended to be used. Premature setting can render the material unusable as it becomes hard and loses its workability. By storing Plaster of Paris in a moisture-proof container, the contact with water is prevented, ensuring that it remains in a dry state until ready for use.

3. Maintaining consistency:
Moisture absorption can alter the consistency of Plaster of Paris. When it absorbs moisture, it becomes lumpy and difficult to mix, leading to an inconsistent and uneven mixture. Storing it in a moisture-proof container prevents moisture from entering, thus maintaining the powder's dry and powdery consistency.

4. Extending shelf life:
Moisture can accelerate the degradation process of Plaster of Paris, reducing its shelf life. By storing it in a moisture-proof container, the exposure to moisture is minimized, allowing the material to last longer and remain usable over an extended period.

Conclusion:
Storing Plaster of Paris in a moisture-proof container is essential to preserve its chemical properties, prevent premature setting, maintain consistency, and extend its shelf life. By ensuring it remains dry, Plaster of Paris can be effectively used for various applications without compromising its quality and performance.