Question 40 (Textile Engineering & Fibre Science)
Determine the correctness or otherwise of the following Assertion [a] and Reason [r].
[a]: Acrylic fibres are dyed with basic dyes in acidic medium.
[r]: In acidic medium the acrylic fibre acquires positive charge.
|(A)||Both [a] and [r] are true and [r] is the correct reason for [a]|
|(B)||Both [a] and [r] are true but [r] is not the correct reason for [a]|
|(C)||Both [a] and [r] are false|
|(D)||[a] is true but [r] is false|
Frequently Asked Questions | FAQs
What is called acrylic fibre?
Acrylic fiber is a synthetic fiber made from a polymer called polyacrylonitrile. It is a type of man-made textile fiber that is often used as a substitute for wool in clothing, blankets, and other textiles. Acrylic fiber is lightweight, soft, and warm, and it can be made in a variety of colors and textures. It is also resistant to wrinkles, mildew, and moths, making it a popular choice for outdoor and sports clothing. Additionally, acrylic fiber is easy to care for and can be machine-washed and tumble-dried.
What are the basic dyes?
Basic dyes are a type of synthetic dye that are cationic, which means they have a positive charge. They are typically used to dye materials such as acrylic, nylon, and silk, as well as some types of paper.
Some examples of basic dyes include:
Methylene Blue: This is a deep blue dye that is commonly used in biology and medicine to stain cells and tissues for microscopic examination.
Crystal Violet: Also known as gentian violet, this is a purple dye that is often used to stain bacteria in microbiology.
Rhodamine B: This is a bright pink dye that is commonly used in fluorescent microscopy and as a marker in biology experiments.
Basic Yellow 40: This is a yellow dye that is often used to color plastics, textiles, and paper.
Basic Red 22: This is a red dye that is commonly used to color textiles, paper, and leather.
Basic dyes are known for their bright, intense colors and ability to bind strongly to fibers, resulting in long-lasting color. However, they can also be more difficult to work with than other types of dyes, as they are often less soluble in water and require more acidic conditions for dyeing.
What are the acid dyes?
Acid dyes are a type of synthetic dye that are anionic, which means they have a negative charge. They are called “acid” dyes because they are typically used to dye protein fibers such as wool, silk, and leather in an acidic environment.
Some examples of acid dyes include:
Acid Red: This is a bright red dye that is often used to dye wool and silk.
Acid Blue: This is a blue dye that is commonly used to dye silk, wool, and nylon.
Acid Yellow: This is a yellow dye that is often used to dye wool, silk, and nylon.
Acid Orange: This is an orange dye that is commonly used to dye wool and silk.
Acid Black: This is a black dye that is often used to dye silk and wool.
Acid dyes are known for their excellent lightfastness and washfastness, which means that they can resist fading or running when exposed to light or water. They are also highly soluble in water and can be easily applied to fibers. However, acid dyes can only be used on protein fibers and are not suitable for dyeing synthetic fibers or cellulose fibers such as cotton or rayon.