Which of the following statements are correct?
A. Arsenic is used in wood preservative. B. CrO42−​ is water soluble. C. Arsenic is not a metal. D. Fe3+ is more soluble compared to Fe2+ in pure water. E. PbS and PbCO3​ are highly insoluble in water.
Choose the most appropriate answer:

Correct option is D

1. Arsenic is used in wood preservative (A - Correct):
· Arsenic compounds like chromated copper arsenate (CCA) have been used in wood preservation to prevent decay and insect damage.
2. CrO42−​ is water soluble (B - Correct):
· Chromates ( CrO42−​) are soluble in water and are commonly used in industrial processes.
3. Arsenic is not a metal (C - Correct):
· Arsenic is a metalloid, possessing properties of both metals and non-metals.
4. Fe3+ is more soluble compared to Fe2+ in pure water (D - Incorrect):
· Fe2+ is generally more soluble in water than Fe3+ because Fe3+ tends to hydrolyze and form insoluble hydroxides.
5. PbS and PbCO3​ are highly insoluble in water (E - Correct):
· Both lead sulfide (PbS) and lead carbonate (PbCO3​) are known for their poor solubility in water, contributing to their environmental persistence.
Additional Knowledge: 1. Arsenic (A):
· Toxicity: Long-term exposure to arsenic causes health issues like cancer and skin lesions.
· Regulations: Many countries have restricted its use in wood preservation due to health concerns.
2. Chromates (B):
· Applications: Widely used in pigments, leather tanning, and metal coatings.
· Toxicity: Chromium compounds, particularly hexavalent chromium, are carcinogenic.
3. Iron Solubility (D):
· Fe2+ is more stable in reducing conditions, while Fe3+ precipitates as hydroxides in oxidizing conditions.
4. Lead Compounds (E):
· Environmental Concerns: Lead compounds contaminate soil and water but persist due to their low solubility.