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PCAT Chemical Processes – Butane

  • by Sam
  • Jan 03, 2018
  • PCAT Question of the Day

Which of the following characterizes butane?

  1. high solubility in water
  2. strong dipole moment
  3. high molecular weight
  4. low solubility in water
Click for Explanation

Butane is a four carbon alkane. As such, it is non-polar and low in molecular weight. Solubility in water is primarily governed by polarity and ability to hydrogen-bond, both of which butane lacks. Choice d is the best choice, low solubility in water.

  1. high solubility in water, incorrect, Nonpolar compounds do not dissolve well in water.
  2. strong dipole moment, incorrect, Alkanes lack dipole moments.
  3. high molecular weight, incorrect, A four carbon alkane has low molecular weight. High molecular weight on the MCAT is often used to describe long-chain polymers and very large molecules, and butane does not qualify for either designation.
  4. low solubility in water, correct.

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