Metals in general have a tendency to evolve hydrogen gas o reacting with acids. In the activity series the metals that are placed above hydrogen evolve the gas on reaction with acids while the metals placed below hydrogen do not evolve the gas on reaction with acids. these metals are regarded as inactive metals. metals placed at the bottom of the series are called noble metals.
Q. Silver and gold do not react with oxygen even at very high temperature while copper reacts on prolonged heating. the reactivity of these metals is

Options

A. `Cu gt Ag gt Au`
B. `Cu=Ag gt Au`
C. `Cu=Ag=Au`
D. `Au gt Cu gt Ag`

Explanation

To determine the reactivity of metals such as silver, gold, and copper in relation to their reaction with oxygen, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Reactivity Series**:
- The reactivity series is a list of metals arranged in order of decreasing reactivity. Metals that are more reactive will displace less reactive metals from their compounds and will react with acids to produce hydrogen gas.

2. **Identifying the Metals**:
- In this case, we are considering three metals: copper (Cu), silver (Ag), and gold (Au).

3. **Observing Reactivity with Oxygen**:
- Silver and gold do not react with oxygen even at high temperatures. This indicates that they are less reactive than copper.
- Copper, on the other hand, reacts with oxygen upon prolonged heating, which shows that it is more reactive than silver and gold.

4. **Arranging the Metals in Order of Reactivity**:
- Based on their behavior towards oxygen:
- Copper is more reactive than silver and gold.
- Silver is more reactive than gold.
- Therefore, the order of reactivity is: **Copper > Silver > Gold**.

5. **Conclusion**:
- The reactivity of these metals can be summarized as follows:
- Copper reacts with oxygen when heated for a long time.
- Silver and gold do not react with oxygen, indicating their lower reactivity.
- Thus, the correct order of reactivity is Copper (most reactive) > Silver > Gold (least reactive).