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Which ONE of the following compounds has the HIGHEST vapour pressure? A - NSC Physical Sciences - Question 1 - 2019 - Paper 2
Question 1
Which ONE of the following compounds has the HIGHEST vapour pressure? A. HCOOH B. CH3CHO C. CH3CH2OH D. CH3CH2CH3
Worked Solution & Example Answer:Which ONE of the following compounds has the HIGHEST vapour pressure? A - NSC Physical Sciences - Question 1 - 2019 - Paper 2
Step 1
Identify the Compound with the Highest Vapour Pressure
Answer
Among the options given:
- HCOOH (Formic Acid): This is a carboxylic acid with hydrogen bonding, leading to lower vapour pressure.
- CH3CHO (Acetaldehyde): Has relatively higher vapour pressure due to the presence of a polar carbonyl group but no significant hydrogen bonding.
- CH3CH2OH (Ethanol): This alcohol has hydrogen bonding, which also results in a lower vapour pressure compared to aldehydes.
- CH3CH2CH3 (Propane): This alkane has no polar functional groups, hence it can be expected to have the highest vapour pressure due to weak van der Waals forces.
Thus, the compound with the highest vapour pressure is D. CH3CH2CH3 (Propane).