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Surface Chemistry — Chemistry STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceChemistrySurface Chemistry3 Marks
Question
Explain the following observations:
  1. Lyophilic colloid is more stable than lyophobic colloid.
  2. Coagulation takes place when sodium chloride solution is added to a colloidal solution of ferric hydroxide.
  3. Sky appears blue in colour.
✓

Answer

  1. The strong force of attraction between the dispersed phase and the dispersion medium make lyophilic Sols more stable.
  2. Positive charge on $Fe(OH)_3$ sol particles get neutralised by $Cl^-$ ions from $NaCl.$
  3. Due to Tyndall effect/or the suspended particles in the atmosphere scatter the incident light.

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