NEET2006ChemistrySurface ChemistryActual
Assertion : Fe ³⁺ can be used for coagulation of As ₂ ~S ₃ sol. Reason : Fe ³⁺ reacts with As ₂ ~S ₃ to give Fe ₂ ~S ₃ .
Options
- AIf both assertion and reason are true and reason is the correct explanation of the assertion
- BIf both assertion and reason are true but reason is not the correct explanation of the assertion
- CIf assertion is true, but reason is false
- DBoth assertion and reason are false statements.
Correct answer
C. If assertion is true, but reason is false
Step-by-step solution
When oppositely charged sols are mixed in almost equal proportions, their charges are neutralised. Both sols may be partially or completely precipitated. When negatively charged As ₂ ~S ₃ sol is added to positively charged Fe ( OH )₃ sol, in suitable amounts, precipitation of both the sols take place simultaneously.