Assertion: In sodium formate, both the `C - O` bonds have same value `1.27 Å`
Reason : Equal bond length is due to the phenomenon of resonance.

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 question, we need to evaluate the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that in sodium formate (HCOONa), both the C-O bonds have the same length of 1.27 Å.

**Hint:** Recall the structure of sodium formate and how the bonds are arranged.

### Step 2: Examine the Structure of Sodium Formate
Sodium formate consists of a formate ion (HCOO⁻) and sodium ion (Na⁺). The formate ion can be represented as follows:

- One structure has a double bond between carbon and one oxygen (C=O) and a single bond with the other oxygen (C-O).
- The other structure has the double bond with the other oxygen, and the first oxygen now has a single bond.

This indicates that the formate ion has resonance structures.

**Hint:** Think about how resonance affects bond lengths and bond orders.

### Step 3: Understand the Concept of Resonance
Resonance is a phenomenon where a molecule can be represented by two or more valid Lewis structures. The actual structure of the molecule is a hybrid of these resonance forms.

In the case of sodium formate, the resonance leads to an equal distribution of the double bond character between the two C-O bonds. This results in both C-O bonds having the same bond length.

**Hint:** Consider how resonance leads to an average bond order.

### Step 4: Conclusion on the Assertion
Since both C-O bonds have the same bond length of 1.27 Å due to resonance, the assertion is correct.

### Step 5: Evaluate the Reason
The reason states that the equal bond length is due to the phenomenon of resonance. This is indeed true as explained in the previous steps.

**Hint:** Reflect on how the explanation of resonance directly supports the assertion.

### Final Conclusion
Both the assertion and the reason are correct, and the reason correctly explains the assertion.

### Answer
The correct option is: Both assertion and reason are true, and the reason is the correct explanation of the assertion.