Environmental Chemistry · JEE Main previous year questions

2018 1 question

1. Q902018 · 8 Apr 2018 · Shift 1

   The recommended concentration of fluoride ion in drinking water is up to 1 ppm as fluoride ion is required to make teeth enamel harder by converting $[3{\text{Ca}}_3({\text{PO}}_4{)}_2.\text{Ca}(\text{OH}{)}_2]$ to

   1. A.$[3\{\text{Ca}(\text{OH}{)}_2\}.{\text{CaF}}_2]$
   2. B.$[{\text{CaF}}_2]$
   3. C.$[3({\text{CaF}}_2).\text{Ca}(\text{OH}{)}_2]$
   4. D.$[3{\text{Ca}}_3({\text{PO}}_4{)}_2.{\text{CaF}}_2]$
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   Answer: D