Organic Chemistry 1 · Functional groups and connectivity
Boiling points of four compounds near 74 g/mol
Conditions: Molar masses about 72–74 g/mol; 1 atm.
Draw this problem yourself
Drag from the electrons that move to where they go, or tap one and then the other. Every arrow is checked; Hint helps when you're stuck. No account needed.
The question
Order from lowest to highest boiling point: propanoic acid, 1-butanol, butanal, diethyl ether.
Reveal the answer and explanation
Answer and explanation
Correct order, from lowest boiling point to highest boiling point
- diethyl ether
No O–H donor and a weak C–O–C dipole: 35 °C.
- butanal
Strong C=O dipole–dipole attraction but no hydrogen-bond donor: 75 °C.
- 1-butanol
O–H donates and accepts hydrogen bonds: 118 °C.
- propanoic acid
Carboxylic acids pair into doubly hydrogen-bonded dimers: 141 °C.
Worked solution
With molar mass nearly equal, the functional group decides. Diethyl ether has only weak dipole forces (35 °C); butanal has a stronger C=O dipole (75 °C); 1-butanol donates and accepts hydrogen bonds (118 °C); propanoic acid forms hydrogen-bonded dimers with two H-bonds each (141 °C).
What you'll practice
Rank oxygen compounds of nearly equal molar mass by boiling point from the intermolecular forces their functional groups allow.
You just pushed every arrow of this one.
Every one of the 5349 Orgo 1 and Orgo 2 problems works like this: feedback on each arrow, hints when you're stuck, a no-hint quiz mode. Free with an account, no card.
Stuck on your own homework?
Snap it — first scan free, no sign-up
Scanning every week? Scan Standard: for about problems