Which of the following will show Tyndall effect?

  1. Aqueous solution of soap below critical micelle concentration
  2. Aqueous solution of soap above critical micelle concentration
  3. Aqueous solution of Sodium Chloride
  4. Aqueous solution of Sugar

Answer (Detailed Solution Below)

Option 2 : Aqueous solution of soap above critical micelle concentration
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Detailed Solution

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The correct answer is Option 2.
Key Points

  • The Tyndall effect is the scattering of light as a light beam passes through a colloid.
  • The individual suspension particles scatter and reflect light, making the beam visible.
  • The Tyndall effect was first described by 19th-century physicist John Tyndall.
  • In associated colloids, the formation of micelles takes place only above a particular temperature called Kraft temperature ​and above a particular concentration called critical micelle concentration (CMC).
  • Below CMC, soap doesn't act as a colloid.
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