This set of Organic Chemistry Multiple Choice Questions & Answers (MCQs) focuses on “Physical Properties of Ketones”.
1. Which of the following compound has more boiling point than ketones?
a) Alcohol
b) Alkanes
c) Aldehyde
d) Ether
View Answer
Explanation: Amongst aldehydes and ketones, ketones have higher boiling point. This is due to the presence of two electron donating alkyl groups around the group which makes them more polar. As dipole moment is greater so it is more polar and hence has higher boiling point. However, the aldehyde’s boiling point isn’t as high as the alcohol’s. In the alcohol, there is hydrogen bonding as well as the other two kinds of intermolecular attraction.
2. Which of the following has highest boiling point?
a) 2-hexanone
b) 2-pentanone
c) butanoic acid
d) 3-methyl-2-butanone
View Answer
Explanation: 2-hexanone has a carbon chain length of 6 whereas 2-pentanone has a carbon chain length of 5. 2-hexanone therefore has a higher boiling point than 2-pentanone. Therefore, the descending order of all four of the provided compounds is butanoic acid, 2-hexanone, 2-pentanone then 3-methyl-2-butanone. It can also be concluded that the boiling point of compounds are affected by the strength of the intermolecular forces present, the chain length of the carbon backbone of the compound and the presence of any branching within its structure.
3. Which of the following is more volatile?
a) Carboxylic acid
b) Alcohol
c) Ketones
d) Aldehyde
View Answer
Explanation: Because of their inability to serve both as hydrogen-bond donors and acceptors, ketones tend not to “self-associate” and are more volatile than alcohols and carboxylic acids of comparable molecular weights.
4. Why ketones are volatile in nature?
a) Due to molecular weight
b) Hydrogen bonding
c) Neither hydrogen bond donor nor acceptor
d) Weak bonding
View Answer
Explanation: Because of their inability to serve both as hydrogen-bond donors and acceptors, ketones tend not to “self-associate” and are more volatile than alcohols and carboxylic acids of comparable molecular weights.
5. Why ketones are used as solvent?
a) Due to molecular weight
b) Hydrogen bonding
c) Neither hydrogen bond donor nor acceptor
d) Weak bonding
View Answer
Explanation: Because of their inability to serve both as hydrogen-bond donors and acceptors, ketones tend not to “self-associate” and are more volatile than alcohols and carboxylic acids of comparable molecular weights. These factors relate to the pervasiveness of ketones as solvents.
6. Which of the ketones are used in nail paint removers?
a) Cyclopropenone
b) Isopropyl acetone
c) butanone
d) Methyl ethyl ketone
View Answer
Explanation: Isopropyl Acetone is a commonly used solvent and is the active ingredient in nail polish remover and some paint thinners.
7. Which of the following is the used as solvent in gums, resins, nitrocellulose?
a) Cyclopropenone
b) Isopropyl acetone
c) butanone
d) Methyl ethyl ketone
View Answer
Explanation: Butanone is an effective and common solvent and is used in processes involving gums, resins, cellulose acetate and nitrocellulose coatings and in vinyl films.
8. Which of the following is also known as model cement?
a) Cyclopropenone
b) butanone
c) Isopropyl acetone
d) Methyl ethyl ketone
View Answer
Explanation: As butanone dissolves polystyrene and many other plastics, it is sold as “model cement” for use in connecting parts of scale model kits.
9. Which of the following is a toxic ketone?
a) butanone
b) Acetone
c) Methyl ethyl ether
d) Methyl vinyl ketone
View Answer
Explanation: Although it is difficult to generalize on the toxicity of such a broad class of compounds, simple ketones are, in general, not highly toxic. Exceptions to this rule are the unsaturated ketones such as methyl vinyl ketone with LD50 of 7 mg/kg (oral).
10. Which of the following cannot be used for the characterisation of ketone by spectroscopy?
a) 1H NMR
b) Infra-red spectrum
c) 13C NMR
d) UV spectroscopy
View Answer
Explanation: Ketones absorb strongly in the infra-red spectrum near 1700 cm−1. The exact position of the peak depends on the substituents. Whereas 1H NMR spectroscopy is generally not useful for establishing the presence of a ketone, 13C NMR spectra exhibit signals somewhat downfield of 200 ppm depending on structure.
Sanfoundry Global Education & Learning Series – Organic Chemistry.
To practice all areas of Organic Chemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.
- Practice Chemical Engineering MCQs
- Apply for Chemical Engineering Internship
- Check Chemical Engineering Books
- Check Organic Chemistry Books
