To analyze the given statements, we will break down the assertion (A) and the reason (R) step by step.
### Step 1: Understanding the Assertion (A)
**Assertion (A)**: H₂O is the only hydride of the chalcogen family that is liquid.
- The chalcogen family consists of elements in Group 16 of the periodic table, which includes oxygen (O), sulfur (S), selenium (Se), tellurium (Te), and polonium (Po).
- Among the hydrides of these elements, H₂O (water) is unique because it exists in a liquid state at room temperature.
- Other hydrides such as H₂S (hydrogen sulfide), H₂Se (hydrogen selenide), and H₂Te (hydrogen telluride) are gases at room temperature.
**Conclusion for Step 1**: The assertion is true because of the strong hydrogen bonding in water, which allows it to remain liquid.
### Step 2: Understanding the Reason (R)
**Reason (R)**: The acidic nature of hydrides of the chalcogen family increases down the group.
- The acidic nature of hydrides generally refers to their ability to donate protons (H⁺) in solution.
- As we move down the group from H₂O to H₂S, H₂Se, and H₂Te, the acidic character does indeed increase.
- This is because the bond strength of H-X (where X is the chalcogen) decreases down the group, making it easier to release H⁺ ions.
- Additionally, the stability of the conjugate base increases due to the larger atomic size, which allows for better charge dispersion.
**Conclusion for Step 2**: The reason is true as the acidic nature does increase down the group.
### Step 3: Evaluating the Relationship Between A and R
- While both the assertion and reason are true, the reason does not explain the assertion adequately. The assertion focuses on the physical state of H₂O as a liquid, while the reason discusses the acidic nature of the hydrides.
- The presence of hydrogen bonding in H₂O is what allows it to be a liquid, not its acidic nature.
### Final Conclusion
- Assertion (A) is true.
- Reason (R) is true, but it does not explain assertion (A).
- Therefore, the correct answer is that both statements are true, but the reason does not support the assertion.
