WAEC 2024 Dyeing & Bleaching Essay & Obj Answers

WAEC dyeing and bleaching

DYEING OBJ
01-10: DBCBAAAABA
11-20: CBAABCDADC
21-30: BADADCBBAB
31-40: BACBDDDCBC

COMPLETED

WAEC DYEING AND BLEACHING ESAAYS

(1a) Color refers to the visual perception resulting from the spectrum of light interacting with the human eye.

(1bi) Primary colors are hues that cannot be created by mixing other colors together. They are typically red, blue, and yellow.
(1bii) Secondary colors are hues formed by mixing two primary colors. Examples include green (blue + yellow), orange (red + yellow), and purple (red + blue).
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(2a) Safety precautions are measures taken to prevent accidents, injuries, or other adverse incidents.

(2b)
(i) gloves
(ii) goggles
(iii) Aprons.

(2c)
(i) Wearing protective clothing such as lab coats or aprons.
(ii) Using gloves to protect hands from chemical exposure.
(iii) Ensuring proper ventilation to reduce inhalation of fumes.
(iv) Following proper handling and storage procedures for chemicals.
(v)Having emergency eyewash stations and showers readily accessible.

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(3a) Three materials used to resist dye in bulk production are wax, starch, and synthetic resins.

(3bi) Steps for waxing fabric using a tjanting:
(i) Heat the wax to a liquid state.
(ii) Load the tjanting tool with wax.
(iii) Apply the wax to the fabric in desired patterns.

(3bii)
(i) Apply wax to the foam.
(ii) Press the foam onto the fabric to transfer the wax.
(iii) Repeat the process to cover the desired areas.

(3biii)
(i) Dip the brush into melted wax.
(ii) Paint the wax onto the fabric in desired designs.
(iii) Allow the wax to cool and harden before dyeing.

(3biv)
(i) Coat the stamp with melted wax.
(ii)Press the stamp onto the fabric to transfer the wax design.
(iii) Repeat the stamping process as needed for the desired pattern.

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(4a) Printing is a process of transferring ink or pigment onto a substrate, such as paper or fabric, to create designs or images.

(4b)
(i) screen printing
(ii) digital printing
(iii) block printing
(iv) sublimation printing.

(4c)
(i) Prepare the design to be printed on a computer.
(ii) Create a screen with a mesh stretched over a frame.
(iii) Apply a light-sensitive emulsion to the mesh and let it dry.
(iv) Expose the screen to UV light with the prepared design to harden the emulsion.
(v) Rinse the screen to wash away the unhardened emulsion, revealing the design.
(vi) Set up the fabric to be printed on a flat surface.
(vii) Position the screen over the fabric and apply the lacquer over the mesh.
(viii) Use a squeegee to evenly spread the lacquer over the mesh, transferring the design onto the fabric.

(5a)
(i)Chlorine bleach (sodium hypochlorite)
(ii)Hydrogen peroxide
(iii)Sodium percarbonate (oxybleach)
(iv)Sodium chlorite

(5b)

(i)Disinfection: Bleaching kills bacteria, viruses, and other pathogens, making it effective for disinfecting surfaces, water, and laundry.
(ii)Whitening: Bleaching can remove stains and whiten fabrics, making them look brighter and cleaner.
(iii) Deodorizing: Bleaching agents can help eliminate unpleasant odors by breaking down organic compounds that cause them.
(iv)Mold and mildew removal: Bleach is effective in killing and preventing the growth of mold and mildew on surfaces like tiles, grout, and bathroom fixtures.
(v)Water treatment: Bleaching is used in water treatment processes to remove impurities and disinfect water for safe consumption.