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Assertion : Soluable fluoride is often a...

Assertion : Soluable fluoride is often added to drinking water to bring its concentration up to 1 ppm.
Reason : `F^(-)` ion concentration above 2 ppm causes brown mottling of teeth.

A

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

B

If both assertion and reason are true but reason is not the c orrect explanation of assertion.

C

If assertion is true but reason is false.

D

If both assertion and reason are false.

Text Solution

Verified by Experts

The correct Answer is:
b
`F^(-)` ions make the enamel on teeth much harder by converting hydroxyapatite, the enamel on the surface of the teeth, into much harder fluorapatite ` [ 3 ( Ca_(3) (PO_(4)) _(2)) .Ca (OH)_(2)], ` the enamel on the surface of the teeth , into much harder fluorapatite ` [ 3 (Ca_(3) (PO_(4))_(2)).CaF_(2)].`
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