Which of the following statement(s) is/are correct?

Options

A. The Chief ore of zinc is cinnabar
B. Mac-Arther's process is used to extract silver
C. `Na_(2)S_(2)O_(3)` is used to remove the unexposed AgBr from the photographic films
D. Nessler's reagent is complex of zinc in +2 oxidation state

Answer

To determine which of the statements regarding d-block elements are correct, let's analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: "Cheap ore of zinc is snubber."**
- **Analysis:** The statement claims that "snubber" is the cheap ore of zinc. However, the correct ore of zinc is "sphalerite," which is primarily composed of zinc sulfide (ZnS). "Snubber" is not an ore of zinc but rather an ore of mercury (HgS).
- **Conclusion:** This statement is **incorrect**.

2. **Statement 2: "MacArthur process is used to extract silver."**
- **Analysis:** The MacArthur process, also known as the cyanide process, is indeed used for the extraction of silver and gold. In this process, the metal is treated with sodium cyanide (NaCN) in the presence of oxygen and water, forming a soluble complex. This complex can then be treated with zinc to recover the pure metal.
- **Conclusion:** This statement is **correct**.

3. **Statement 3: "Na2SO3 is used to remove unexposed AGBR from photographic film."**
- **Analysis:** The statement refers to sodium thiosulfate (Na2S2O3), which is indeed used in photography to remove unexposed silver bromide (AgBr) from developed photographic film. This compound forms a soluble complex with silver ions, effectively removing them from the film.
- **Conclusion:** This statement is **correct**.

4. **Statement 4: "Nessler's reagent is a complex of zinc in +2 oxidation state."**
- **Analysis:** Nessler's reagent is actually potassium tetraiodomercurate(II), K2HgI4, which is a complex of mercury, not zinc. Therefore, this statement is incorrect as it misidentifies the metal involved.
- **Conclusion:** This statement is **incorrect**.

### Final Conclusion:
The correct statements are:
- Statement 2: "MacArthur process is used to extract silver."
- Statement 3: "Na2SO3 is used to remove unexposed AGBR from photographic film."

### Summary of Correct Statements:
- **Correct Statements:** 2 and 3
- **Incorrect Statements:** 1 and 4

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