Which is/are correct statements?

Options

A. Oxidation product of 1,2-ethanediol with `HlO_(4)` is formaldehyde
B. `1^(@)` alcohol turns `K_(2)Cr_(2)O_(7)//H^(+)` solution green
C. t-Butyl alcohol is converted to isobutene on heating with Cu
D. `CH_(3)OH` is also called wood spirit

Answer

To determine which statements are correct regarding the oxidation and reactions of alcohols, let's analyze each option step by step.

### Step 1: Analyze the first statement
**Statement:** The oxidation product of 1,2-ethanediol (ethylene glycol) with HIO4 results in formaldehyde.

**Explanation:**
1. 1,2-Ethanediol (ethylene glycol) is a vicinal diol (cis-diol).
2. When oxidized with periodic acid (HIO4), it cleaves the carbon-carbon bond between the two hydroxyl groups.
3. This results in the formation of two molecules of formaldehyde (HCHO), which is indeed the correct product.

**Conclusion:** This statement is correct.

### Step 2: Analyze the second statement
**Statement:** A 1-degree alcohol reacts with K2Cr2O7 in acidic medium, turning the solution green.

**Explanation:**
1. A 1-degree alcohol can be represented as R-CH2-CH2OH.
2. When it reacts with potassium dichromate (K2Cr2O7) in acidic conditions, it gets oxidized to an aldehyde.
3. The chromium in K2Cr2O7 has an oxidation state of +6, which gives the solution an orange color.
4. Upon reduction to chromium (III) in the process, the color changes to green.

**Conclusion:** This statement is correct.

### Step 3: Analyze the third statement
**Statement:** Tert-butyl alcohol is converted to isobutene on heating with copper.

**Explanation:**
1. Tert-butyl alcohol (2-methyl-2-propanol) can undergo dehydration when heated in the presence of copper.
2. This dehydration process leads to the formation of a stable tertiary carbocation.
3. The elimination of water (H2O) results in the formation of isobutene (2-methylpropene).

**Conclusion:** This statement is correct.

### Step 4: Analyze the fourth statement
**Statement:** Methanol (CH3OH) is referred to as wood spirit.

**Explanation:**
1. Methanol is indeed known as wood spirit due to its historical production from the destructive distillation of wood.
2. It is a light, volatile, flammable, and poisonous liquid.
3. Methanol is commonly used as an antifreeze and solvent.

**Conclusion:** This statement is correct.

### Final Conclusion
All four statements are correct.