JEE Main 2022 · 24 Jun · Shift 1 · Chemistry Q72

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ChemistrySingle correct+4 / -1Question 72 of 90

Which one of the following elemental forms is not present in the enamel of the teeth ?

\mathrm{Ca^{2+}}

\mathrm{P^{3+}}

\mathrm{F^-}

\mathrm{P^{5+}}

Answer and worked solution

Official answer: B

Enamel is mainly hydroxyapatite with some fluorapatite, $\mathrm{Ca_5(PO_4)_3F}$ . It contains $\mathrm{Ca^{2+}}$ , $\mathrm{F^-}$ and phosphate, in which phosphorus is $+5$ .

Not present: $\mathrm{P^{3+}}$ .

(B)

Topics:Group 15 Oxidation number

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JEE Main 2022 · 24 Jun · Shift 1, Chemistry question 72