Which of the following metal is NOT used in wood preservatives?

Correct option is D

The correct answer is (d) Pb (Lead). Lead is not typically used in wood preservatives due to its toxicity and environmental concerns. Instead, wood preservatives commonly use Copper (Cu), Chromium (Cr), and Arsenic (As) in formulations like Chromated Copper Arsenate (CCA) to protect against fungi, insects, and decay.
Explanation of Other Options:
· (a) Cu (Copper): Used in wood preservatives like Copper Azole and Alkaline Copper Quaternary (ACQ) for its antifungal and antibacterial properties.
· (b) Cr (Chromium): Present in Chromated Copper Arsenate (CCA) as a fixative to bind the preservative to the wood fibers.
· (c) As (Arsenic): Also a component of CCA, it helps protect wood from insects and decay.
Information Booster: 1. Common Wood Preservatives:
· CCA (Chromated Copper Arsenate): A mixture of copper, chromium, and arsenic used for treating outdoor wood.
· ACQ (Alkaline Copper Quaternary): A copper-based preservative without arsenic, considered safer than CCA.
· Copper Azole: Contains copper and a triazole compound; used in residential and industrial applications.
2. Why Lead is Not Used:
· Lead is toxic and harmful to the environment and humans.
· It accumulates in soil and water, posing health risks.
3. Toxicity Concerns:
· CCA is restricted in many regions for residential use due to arsenic concerns.
· Safer alternatives like ACQ and Copper Azole are now preferred.
4. Applications of Wood Preservatives:
· Outdoor Structures: Decks, fences, and playground equipment.
· Industrial Uses: Utility poles and railway sleepers.
Additional Knowledge: · Pb (Lead): Historically used in paints and pipes but now phased out due to health hazards.
· Cu (Copper): Offers protection against fungi and bacteria.
· Cr (Chromium): Acts as a fixative in preservatives to ensure durability.
· As (Arsenic): Provides insecticidal properties in wood treatments.