Question

Lithopone is a mixture of (a) barium sulphate and rinc sulphide (b) barium sulphide and zinc sulphide (c) calcium sulphate and zine sulphide (d) calcium sulphide and rine sulphide

Short answer

Lithopone is a mixture of barium sulphate and zinc sulphide, which corresponds to option (a).

Step-by-step solution

Understand the Composition of Lithopone

Lithopone is a white pigment used in paints and coatings. It is known to be made up of two main components: barium sulfate and zinc sulfide. These components are mixed to give lithopone its desired properties such as better covering power and light stability.

Analyze the Options Given

We have four options for the composition of lithopone: (a) barium sulphate and zinc sulphide (b) barium sulphide and zinc sulphide (c) calcium sulphate and zinc sulphide (d) calcium sulphide and zinc sulphide We need to identify which pair matches the traditional composition of lithopone.

Match the Components to Options

From our understanding in Step 1, lithopone is known to contain barium sulfate and zinc sulfide. Comparing this to the given options, only option (a) has the correct components that form lithopone.

Confirm the Correct Option

Re-evaluate the reasoning to ensure no mistakes were made in matching the components. After reviewing, we confirm that option (a) indeed includes both barium sulphate and zinc sulphide, which are the components of lithopone.

Key concepts

Barium Sulfate

Barium sulfate is a naturally occurring mineral used in a variety of applications. One of its key roles is in the pigment industry, particularly in the creation of lithopone. Barium sulfate provides certain qualities that make it highly desirable in this context. It is insoluble, non-toxic, and provides a base that contributes to the stability and brightness of pigments.

Barium sulfate works by adding density and opacity to paints. This helps in improving the covering power of paint, allowing it to hide what's underneath effectively. It also reflects light well, contributing to the brightness of white pigments like lithopone.

• Enhances paint's opacity
• Non-reactive; doesn’t affect other components
• Increases stability of the pigment

Understanding its role in pigment formulation helps appreciate why barium sulfate is a staple component in industries focused on coatings and paints.

Zinc Sulfide

Zinc sulfide is another crucial component in the production of pigments like lithopone. Known for its photoluminescent properties, zinc sulfide is often used when creating pigments that need to maintain color stability even when exposed to light.

In addition to its lightfastness, zinc sulfide also provides excellent dispersion in formulations, meaning it blends evenly without clumping. This ability results in smoother applications, especially important in paints to ensure uniform surface coverage.

• Gives resistance to light-induced fading
• Ensures even dispersion in paint mixtures

Zinc sulfide's unique properties make it indispensable in producing high-quality pigments for various applications, from residential paints to more specialized industrial coatings.

White Pigment

White pigments, like lithopone, play an essential role in the paint and coatings industries. They are valued for their ability to provide opacity and reflectance, completely masking surfaces beneath them. This makes them ideal for many applications not only due to their hiding power but also their aesthetic appeal.

One key advantage of white pigments is their versatility. They can be combined with other pigments to create almost any color while maintaining opacity. White pigments need to be highly stable to endure various environmental factors that can degrade paint surfaces over time. Lithopone is particularly noted for being non-yellowing, even when exposed to sunlight.

• Provides excellent opacity and coverage
• Non-yellowing characteristic ideal for exterior use
• Can be tinted to create a wide range of colors

These qualities make white pigments incredibly valuable in designing and maintaining the appearance of architectural and decorative surfaces.

Paint Composition

Understanding paint composition is crucial for those involved with its application and selection. Paint is comprised of several key ingredients, and pigments like lithopone are just one component. The basic elements of paint include the pigment, binder, solvent, and additives.

• Pigment: Provides color, opacity, and protection. In lithopone, the pigment component is particularly important for whiteness and hiding power.
• Binder: Holds the pigment particles together and provides adhesion to the surface.
• Solvent: Adjusts the viscosity, allowing the paint to be applied smoothly.
• Additives: Enhance specific properties such as drying time or resistance to mold.

The choice of each component influences the performance and appearance of the final paint product. Selecting the right type and combination of ingredients is key to resolving specific application requirements such as durability, finish, and color retention.