Question

Identify the correct statements from the following:
i. Reaction of hydrogen with fluorine occurs even in dark.
ii. Manufacture of ammonia by Haber process is an endothermic reaction.
iii. HF is an electron-rich hydride.

• A. \( i, iii \) \(\text{only} \)
• B. \( ii, iii \)
• C. \( ii \text{ only} \)
• D. \( i, ii \text{ only} \)

Hint:

Fluorine is highly reactive and can react in the dark. The Haber process is exothermic, and HF is an electron-rich hydride due to its lone pairs.

Answer 1

The Correct Option is A

Step 1: Analyzing Statement (i) 
- The reaction of hydrogen with fluorine is highly exothermic and occurs spontaneously even in the dark due to fluorine’s high reactivity.
- The reaction is: \[ H_2 + F_2 \rightarrow 2HF \] - Since fluorine is the most electronegative element, it reacts readily without requiring external activation energy.
Conclusion: Statement (i) is correct.
Step 2: Analyzing Statement (ii) 
- The Haber process for ammonia synthesis:
\[ N_2 + 3H_2 \rightleftharpoons 2NH_3 + \Delta H \] has an exothermic enthalpy change (\( \Delta H<0 \)). - Since ammonia formation releases heat, it is not endothermic.
Conclusion: Statement (ii) is incorrect.
Step 3: Analyzing Statement (iii) 
- HF (hydrofluoric acid) is an electron-rich hydride because:
- It has three lone pairs on fluorine.
- It forms strong hydrogen bonds due to high electronegativity.
Conclusion: Statement (iii) is correct.
Step 4: Final Answer 
Since statements (i) and (iii) are correct, the correct answer is: \(Option (1): i, iii \text{ only}\)