Number of metals which lie above hydrogen out of the following is
Sodium, lead, copper, platinum, zinc, mercury.

Explanation

To solve the question regarding the number of metals that lie above hydrogen in the reactivity series from the given list (Sodium, Lead, Copper, Platinum, Zinc, Mercury), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Reactivity Series**: The reactivity series is an arrangement of metals in order of decreasing reactivity. Metals that are more reactive can displace less reactive metals from their compounds.

2. **Identify the Position of Hydrogen**: In the reactivity series, hydrogen is placed in a specific position. Metals that are more reactive than hydrogen will be above it, while those that are less reactive will be below it.

3. **List the Metals Given**: The metals provided in the question are:
- Sodium (Na)
- Lead (Pb)
- Copper (Cu)
- Platinum (Pt)
- Zinc (Zn)
- Mercury (Hg)

4. **Refer to the Reactivity Series**: The typical order of the reactivity series includes:
- Potassium (K)
- Sodium (Na)
- Lithium (Li)
- Barium (Ba)
- Strontium (Sr)
- Calcium (Ca)
- Magnesium (Mg)
- Aluminium (Al)
- Manganese (Mn)
- Zinc (Zn)
- Iron (Fe)
- Tin (Sn)
- Lead (Pb)
- Hydrogen (H)
- Copper (Cu)
- Silver (Ag)
- Gold (Au)
- Platinum (Pt)

5. **Determine Which Metals Are Above Hydrogen**: From the reactivity series, we can see that:
- Sodium (Na) is above hydrogen.
- Zinc (Zn) is above hydrogen.
- Lead (Pb) is above hydrogen.
- Copper (Cu), Platinum (Pt), and Mercury (Hg) are below hydrogen.

6. **Count the Metals Above Hydrogen**: The metals that lie above hydrogen from the given list are:
- Sodium (Na)
- Zinc (Zn)
- Lead (Pb)

7. **Final Count**: Therefore, the total number of metals that lie above hydrogen is **3**.

### Final Answer:
The number of metals which lie above hydrogen out of the given list is **3** (Sodium, Zinc, and Lead).

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