Assertion : Fluorescein is an adsorption indicator Reason : Fluorecsein indicator is a dye.

a.  It both assertion and reason are true and the reason is the correct explanation of the assertion

b. If Both assertion and reason are true but reason is not the correct explanation of the assertion

c. If assertion is true but reason is false

d. If the assertion and reason both are false

e. If assertion is false but reason is true.

Ans. b

Explanation : an adsorption indicator whose colour when adsorbed to the precipitate is different from that when is in solution is used on titrating Cl ^–  and Ag ⁺ . The anionic dye dichlore -fluorescien is used as an indicator.  Before the end point the precipitate of AgCl  has a negative surface charge due to excess Cl ^–l  ion. at the end poind the precipitate has a positive surface charge due to the adsorption of excessAg ⁺  the anionic indictor now adsorbs to the precipitate ‘s surface where its colour is pink this change in colour signals the end poind

Hence both assertion and reason are correct statements but reason is not the correct explanation of the assertion

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