A solid with high electrical and thermal conductivity from the following is

Options

A. Si
B. Li
C. NaCl
D. ice

Explanation

To determine which solid has high electrical and thermal conductivity, we can analyze the properties of the given options. Here’s a step-by-step solution:

### Step 1: Identify the Options
First, we need to identify the solids provided in the question. Common options might include:
- Lithium (Li)
- Sodium Chloride (NaCl)
- Silicon (Si)
- Ice (H2O in solid form)

### Step 2: Analyze Each Option
Next, we will analyze the electrical and thermal conductivity of each solid:

1. **Lithium (Li)**:
- Lithium is an alkali metal.
- Alkali metals have one electron in their outermost shell, which can be easily donated.
- This property allows lithium to conduct electricity very well.
- Being a metal, lithium also has high thermal conductivity.

2. **Sodium Chloride (NaCl)**:
- NaCl is an ionic compound.
- In solid form, NaCl does not conduct electricity because the ions are fixed in place.
- However, when dissolved in water or melted, NaCl can conduct electricity due to the mobility of ions.
- Its thermal conductivity is lower compared to metals.

3. **Silicon (Si)**:
- Silicon is a metalloid and a semiconductor.
- While it can conduct electricity, its conductivity is not as high as that of metals like lithium.
- Silicon has moderate thermal conductivity, but it is not as high as that of metals.

4. **Ice (H2O)**:
- Ice is the solid form of water.
- Ice is a poor conductor of electricity because it lacks free-moving ions.
- Its thermal conductivity is also low compared to metals.

### Step 3: Conclusion
Based on the analysis:
- The solid with high electrical and thermal conductivity is **Lithium (Li)**.

### Final Answer
The correct answer is **Lithium (Li)**.

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