A : Formic acid is the strongest mono carboxylic acid.
R : Trifluoroacetic acid is weaker than formic acid.

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1).
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2).
C. If Assertion is true statement but Reason is false, then mark (3).
D. If both Assertion and Reason are false statements, then mark (4).

Answer

To solve the question regarding the statements about formic acid and trifluoroacetic acid, we will analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** Formic acid is the strongest mono carboxylic acid.

- **Explanation:** Formic acid (HCOOH) is indeed one of the strongest monocarboxylic acids. The strength of an acid is determined by its ability to donate protons (H+ ions). The stability of the conjugate base (A-) formed after the acid donates a proton is crucial. In the case of formic acid, the conjugate base is the formate ion (HCOO-), which is relatively stable due to the resonance stabilization between the two oxygen atoms.

### Step 2: Analyze Statement R
**Statement R:** Trifluoroacetic acid is weaker than formic acid.

- **Explanation:** Trifluoroacetic acid (CF3COOH) has three fluorine atoms attached to the carbon adjacent to the carboxylic group. Fluorine is highly electronegative and exerts a strong -I (inductive) effect, which stabilizes the negative charge on the conjugate base (CF3COO-). This increased stability of the conjugate base makes trifluoroacetic acid a stronger acid than formic acid, contrary to what Statement R claims.

### Conclusion
- **Final Assessment:**
- Statement A is **True**: Formic acid is indeed the strongest monocarboxylic acid.
- Statement R is **False**: Trifluoroacetic acid is stronger than formic acid due to the strong -I effect of the trifluoro group.

Thus, the correct answer is that Statement A is true, and Statement R is false.

---