JEE Main · 2020 · 06 Sep 2020 · Shift 1 · p-Block Elements

The present of soluble fluoride ion upto 1 ppm concentration in drinking water, is:

(A)harmful for teeth
(B)harmful to skin
(C)harmful to bones
(D)safe for teeth✓ Correct

Answer: (D)

Solution

Fluoride in drinking water at low levels, up to about

1 ppm

, is actually beneficial: it is taken into tooth enamel, hardening it and making it more resistant to acid attack, which helps prevent decay. Problems such as dental and skeletal fluorosis appear only at higher concentrations. At

1 ppm

, therefore, fluoride is safe for teeth.

JEE Main · 2020 · 06 Sep 2020 · Shift 1 · Single correct option

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