`PbOhArrPb+1/2O_2, K=2xx10^(-1)`
` ZnOhArr +1/2 O_2 K=2xx10^2`
`CuOhArr +1/2 O_2: K=2xx10^(2)`
`Ag_2OhArr2Ag+1/2 O_2 , K=2xx10^4`
On the basis of equilibrium constant, which of the following is most stable oxide ?

Options

A. ZnO
B. CuO
C. PbO
D. `Ag_2O`

Answer

To determine the most stable oxide based on the given equilibrium constants, we will analyze the provided reactions and their corresponding equilibrium constants step by step.

### Step 1: Understand the Equilibrium Constant
The equilibrium constant (K) indicates the ratio of the concentrations of products to reactants at equilibrium. A smaller value of K suggests that the reactants are favored at equilibrium, indicating greater stability of the reactants (or in this case, the oxides).

### Step 2: List the Reactions and Their Equilibrium Constants
1. \( \text{PbO} \rightleftharpoons \text{Pb} + \frac{1}{2} \text{O}_2, \quad K = 2 \times 10^{-1} \)
2. \( \text{ZnO} \rightleftharpoons \frac{1}{2} \text{O}_2, \quad K = 2 \times 10^{2} \)
3. \( \text{CuO} \rightleftharpoons \frac{1}{2} \text{O}_2, \quad K = 2 \times 10^{2} \)
4. \( \text{Ag}_2\text{O} \rightleftharpoons 2\text{Ag} + \frac{1}{2} \text{O}_2, \quad K = 2 \times 10^{4} \)

### Step 3: Compare the Values of K
Now, we will compare the equilibrium constants:
- \( K_{PbO} = 2 \times 10^{-1} \)
- \( K_{ZnO} = 2 \times 10^{2} \)
- \( K_{CuO} = 2 \times 10^{2} \)
- \( K_{Ag_2O} = 2 \times 10^{4} \)

### Step 4: Identify the Smallest K Value
The smallest K value is \( 2 \times 10^{-1} \) for \( \text{PbO} \). This indicates that at equilibrium, the concentration of products (Pb and O2) is much lower compared to the reactant (PbO), suggesting that PbO is more stable.

### Step 5: Conclusion
Based on the analysis, the most stable oxide among the given options is \( \text{PbO} \).

### Final Answer
The most stable oxide is **PbO**.

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