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Chemistry Chapter 4 : Topic 16
Hydrogen Halide Stability
1 / 20
Which hydrogen halide is most thermally stable due to the strongest H-X bond?
Reasoning: HF has the strongest H-F bond due to small atomic size and high electronegativity of fluorine, making it most resistant to thermal decomposition.
2 / 20
The decreasing order of thermal stability of hydrogen halides is best represented as:
Reasoning: Thermal stability depends on bond strength, which decreases down the group due to increasing atomic size.
3 / 20
Which factor primarily explains why HI is least thermally stable?
Reasoning: Iodine has a large atomic radius, leading to poor orbital overlap and weak bond strength.
4 / 20
If equal amounts of HF, HCl, HBr, and HI are heated strongly, which will decompose first?
Reasoning: HI has the weakest bond, so it decomposes most easily upon heating.
5 / 20
The bond strength of hydrogen halides decreases down the group because:
Reasoning: Larger atoms lead to poorer overlap between hydrogen and halogen orbitals.
6 / 20
Which statement best explains why HF is exceptionally stable compared to other hydrogen halides?
Reasoning: HF has strong H-F bonds and intermolecular hydrogen bonding, enhancing stability.
7 / 20
When hydrogen halides are heated, they decompose according to:
Reasoning: HF has the strongest bond, so it resists decomposition most.
8 / 20
Which of the following correctly relates bond length and thermal stability of HX?
Reasoning: Longer bonds are weaker, making compounds less thermally stable.
9 / 20
The order of bond dissociation energy for HX is:
Reasoning: Bond dissociation energy decreases down the group due to increasing atomic size.
10 / 20
Which hydrogen halide shows the greatest resistance to thermal decomposition due to effective orbital overlap?
Reasoning: Small size of fluorine allows maximum overlap with hydrogen orbitals.
11 / 20
Why does HCl have lower thermal stability than HF but higher than HBr?
Reasoning: Bond strength decreases gradually down the group.
12 / 20
Which property trend directly correlates with thermal stability of hydrogen halides?
Reasoning: Higher bond energy means stronger bonds and greater thermal stability.
13 / 20
A student claims that HI is most stable because iodine is heavier. Why is this incorrect?
Reasoning: Larger atoms lead to weaker bonds due to poor overlap.
14 / 20
Which of the following best explains the trend HF>HCl>HBr>HI in stability?
Reasoning: Bond length increases down the group, reducing bond strength.
15 / 20
If bond strength is directly proportional to thermal stability, which comparison is correct?
Reasoning: HCl has stronger bond than HBr, so it is more stable.
16 / 20
Which hydrogen halide shows maximum tendency to decompose into hydrogen and halogen at moderate heating?
Reasoning: Weakest H-I bond breaks easily.
17 / 20
The main reason for strong H-F bond is:
Reasoning: Small size allows better overlap, increasing bond strength.
18 / 20
Which of the following statements is incorrect regarding hydrogen halides?
Reasoning: Bond strength actually decreases down the group.
19 / 20
Which hydrogen halide would require the least energy to break its bond?
Reasoning: HI has the weakest bond, so it needs least energy.
20 / 20
The trend in thermal stability of hydrogen halides is mainly influenced by:
Reasoning: Thermal stability is directly related to bond dissociation energy.
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