Which of the following forms the most basic hydroxide-

Options

A. `Cu`
B. `Al`
C. `Na`
D. `Zn`

Explanation

To determine which of the given metals forms the most basic hydroxide, we can follow these steps:

### Step 1: Identify the metals given in the options
The metals provided in the options are:
- Copper (Cu)
- Aluminium (Al)
- Sodium (Na)
- Zinc (Zn)

### Step 2: Understand the nature of hydroxides
Hydroxides are compounds that contain the hydroxide ion (OH⁻). The basicity of a hydroxide is determined by how readily it dissociates in water to produce hydroxide ions. The more hydroxide ions produced, the more basic the hydroxide.

### Step 3: Classify the metals
- **Sodium (Na)**: This is an alkali metal, which typically forms strong bases when reacting with water.
- **Copper (Cu)**: This is a transition metal and forms copper hydroxide (Cu(OH)₂), which is not very soluble in water and thus not very basic.
- **Aluminium (Al)**: This is also a transition metal and forms aluminium hydroxide (Al(OH)₃), which is amphoteric and not very basic.
- **Zinc (Zn)**: This is another transition metal that forms zinc hydroxide (Zn(OH)₂), which is also amphoteric.

### Step 4: Compare the basicity of the hydroxides
Among the metals listed:
- Sodium hydroxide (NaOH) is highly soluble in water and dissociates completely to give a high concentration of hydroxide ions, making it very basic.
- Copper, aluminium, and zinc hydroxides are less soluble and do not produce as many hydroxide ions in solution.

### Step 5: Conclusion
Based on the analysis, sodium (Na) forms the most basic hydroxide among the options provided.

### Final Answer
The metal that forms the most basic hydroxide is **Sodium (Na)**.

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