Transition metal which forms green compounds in its `+3` oxidation state and orange red compounds in its `+6` oxidation state is

Options

A. Cobalt
B. Chromium
C. Iron
D. Nickel

Answer

To solve the question regarding the transition metal that forms green compounds in its +3 oxidation state and orange-red compounds in its +6 oxidation state, we can follow these steps:

### Step 1: Identify Transition Metals
Transition metals are elements that have partially filled d-orbitals. They are found in the d-block of the periodic table. Common transition metals include chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).

**Hint:** Look for metals in the d-block of the periodic table.

### Step 2: Examine Oxidation States
The question specifies two oxidation states: +3 and +6. We need to find a transition metal that exhibits these oxidation states and forms compounds with the specified colors.

**Hint:** Recall that transition metals can exhibit multiple oxidation states.

### Step 3: Analyze Color of Compounds
- **+3 Oxidation State:** We need a transition metal that forms green compounds in this state.
- **+6 Oxidation State:** We need a transition metal that forms orange-red compounds in this state.

**Hint:** Research common compounds of transition metals and their associated colors.

### Step 4: Identify Chromium
Chromium (Cr) is a transition metal that fits the criteria:
- In the +3 oxidation state, chromium forms compounds such as Cr₂(SO₄)₃, which are typically green in color.
- In the +6 oxidation state, chromium forms compounds like potassium dichromate (K₂Cr₂O₇), which are orange-red in color.

**Hint:** Look for specific compounds of chromium and their colors.

### Step 5: Conclusion
Based on the analysis, the transition metal that forms green compounds in the +3 oxidation state and orange-red compounds in the +6 oxidation state is chromium (Cr).

**Final Answer:** Chromium (Cr)