Coordination Chemistry

Step 1: Understanding the Question.
The question asks about the physical properties of a substance undergoing a change. We are looking for a reversible change that does not affect the substance's physical properties.
Step 2: Analyzing the Options.
- (A) Describes an irreversible process, which is not correct for this context.
- (B) Describes a change that does not affect the physical state, but the nature of the change is not specified.
- (C) Is the correct answer because it describes a reversible change that preserves the physical properties of the substance.
- (D) Describes an irreversible change, which contradicts the reversible nature of the change in the question.
Step 3: Conclusion.
The correct answer is (C) The substance undergoes a reversible change and retains its physical properties.

Step 1: Understanding the Compound.
In , oxygen has an oxidation state of -2. Since the compound is neutral, the oxidation state of manganese must balance the total charge of oxygen. Thus, the oxidation state of Mn in is +4.
Step 2: Conclusion.
The correct answer is (C) +4.

Step 1: Understanding the Complex.
The complex is , and ammonia (NH ) is a neutral ligand. The charge on the complex is +3, meaning the charge on the central metal ion is +3.
Step 2: Determining Oxidation State and Unpaired Electrons.
For , the oxidation state of Co is +3. In a configuration for , the number of unpaired electrons is 3.
Step 3: Conclusion.
The correct answer is (B) .

Step 1: Identify the complex ion.
The given compound is . The complex part is . Since it is inside square brackets, it is a coordination complex.
Step 2: Determine oxidation state of cobalt.
Each ligand carries a charge of . There are 6 such ligands, so total ligand charge is .
Let oxidation state of Co =
So cobalt is in oxidation state.
Step 3: Identify bonding mode of SCN ligand.
The ligand is ambidentate. If it is attached through nitrogen, it is called isothiocyanato - N.
Step 4: Naming the complex.
Since the complex ion is negative, cobalt will be named as cobaltate (III). The ligand name becomes isothiocyanato - N.
The cation is mercury in +2 oxidation state.
Step 5: Conclusion.
Thus, the correct IUPAC name is Mercury (II) tetraisothiocyanato - N - cobaltate (III).
Final Answer:Mercury (II) tetraisothiocyanato - N - cobaltate (III).

Step 1: Use formula for magnetic moment.
Magnetic moment is given by the spin-only formula:
where is the number of unpaired electrons. Greater the number of unpaired electrons, higher is the magnetic moment.
Step 2: Find unpaired electrons in each ion.

• : Electronic configuration , so it has 4 unpaired electrons.
• : Configuration , has 2 unpaired electrons.
• : Configuration , has 1 unpaired electron.
• : Configuration , usually has fewer unpaired electrons (often low spin).

Step 3: Compare magnetic moments.
Since has the highest number of unpaired electrons (4), it will have the highest magnetic moment.
Step 4: Conclusion.
Therefore, shows the maximum magnetic moment.
Final Answer: .

Step 1: Understand the role of analytical reagents.
In qualitative and quantitative chemical analysis, special reagents are used to detect, separate, or estimate metal ions and other substances. These reagents usually form colored complexes or precipitates, which help in identification and measurement. Step 2: Examine the common analytical reagents.
EDTA is a very important complexometric reagent widely used in quantitative analysis, especially in titrations for hardness of water and estimation of metal ions.
Cupron is used as an analytical reagent for certain metal ions. It is useful in inorganic analysis.
DMG (dimethylglyoxime) is a well-known reagent used for the detection and estimation of nickel, as it forms a characteristic red precipitate with .
Step 3: Identify the reagent not commonly used in chemical analysis.

• (A) EDTA: Used in quantitative chemical analysis.
• (B) Cupron: Used as an analytical reagent.
• (C) DMG: Used in qualitative as well as quantitative analysis of nickel.
• (D) D-penicillamine: Not commonly used as a standard reagent in qualitative and quantitative chemical analysis.

D-penicillamine is better known in coordination chemistry and medicinal applications rather than as a routine analytical reagent used in standard qualitative and quantitative analysis. Step 4: Conclusion.
Hence, the reagent which is not used in qualitative and quantitative chemical analysis is D-penicillamine.
Final Answer:D-penicillamine.