Assertion : For the reaction : `N_(2(g))+3H_(2(g))hArr2NH_(3(g)),K_(p)=K_(c)`
Reason : Concentration of gaseous reactants and products is taken as unity.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To solve the assertion-reason question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that for the reaction:
\[ N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g) \]
it is claimed that \( K_p = K_c \).

### Step 2: Determine the Relationship Between \( K_p \) and \( K_c \)
To determine the relationship between \( K_p \) and \( K_c \), we use the formula:
\[ K_p = K_c (RT)^{\Delta n_g} \]
where \( \Delta n_g \) is the change in the number of moles of gas, calculated as:
\[ \Delta n_g = \text{moles of gaseous products} - \text{moles of gaseous reactants} \]

### Step 3: Calculate \( \Delta n_g \)
For the given reaction:
- Moles of gaseous products (NH3) = 2
- Moles of gaseous reactants (N2 + 3H2) = 1 + 3 = 4

Thus,
\[ \Delta n_g = 2 - 4 = -2 \]

### Step 4: Substitute \( \Delta n_g \) into the Equation
Now substituting \( \Delta n_g \) into the relationship:
\[ K_p = K_c (RT)^{-2} \]
This implies:
\[ K_p = \frac{K_c}{(RT)^2} \]

### Step 5: Conclusion about the Assertion
Since \( K_p \) is not equal to \( K_c \) (it is actually \( K_p = \frac{K_c}{(RT)^2} \)), the assertion is **false**.

### Step 6: Analyze the Reason
The reason states that the concentration of gaseous reactants and products is taken as unity. This is incorrect because in equilibrium expressions for gases, we do not take their concentrations as unity. Instead, we use their actual concentrations or partial pressures.

### Step 7: Conclusion about the Reason
Since the reason is also incorrect, we conclude that both the assertion and the reason are **false**.

### Final Answer
Both the assertion and reason are false. Therefore, the correct option is D: Both assertion and reason are wrong.

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