General Principles And Processes Of Isolation Of Elements

Corrosion is the degradation of metals due to chemical reactions with environmental elements, often oxygen or water. To prevent corrosion, the surface of metals is typically coated with protective substances.
- Phenol: This compound is not typically used for corrosion protection. It is an aromatic alcohol used in various chemical processes.
- Benzene: Benzene is a solvent and is not used for coating metals to prevent corrosion.
- Acetone: Acetone is a solvent and has no role in protecting metals from corrosion.
- Bisphenol: Bisphenol is used in the production of protective coatings like epoxy resins, which are used to prevent corrosion of metallic surfaces. Therefore, it is the correct answer.
- Nitrophenol: This compound is not used for corrosion protection and has other industrial applications.
Thus, the correct answer is (D) Bisphenol, as it is used in the preparation of protective coatings for metals.

The complex is: Outside the bracket there are 2 chloride ions, so the complex cation has charge . Now calculate oxidation state of cobalt: So cobalt is in the +3 oxidation state. The ligand is nitrito. Thus the name is:
Hence, the correct answer is:

Concept: Chemistry - Coordination Compound Nomenclature.
Step 1: Find charge on complex ion. Compound: [ [CoCl_2(en)_2]Cl ] Outer has charge , so complex ion charge is .
Step 2: Find oxidation state of cobalt. Let oxidation state of Co = [ x + 2(-1) + 0 = +1 ] [ x-2=1 ] [ x=+3 ]
Step 3: Name ligands alphabetically. * chlorido * ethane-1,2-diamine Two of each: * dichlorido * bis(ethane-1,2-diamine)
Step 4: Write metal name with oxidation state. [ \text{cobalt(III)} ] Then counter ion = chloride.
Step 5: Final answer. [ \boxed{\text{Dichloridobis(ethane-1,2-diamine)cobalt(III)chloride}} ]
Hence, correct option is (D).