Consider the following reaction and statements:
[Co(NH₃)₄Br₂]⁺ + Br^- $$\to$$ [Co(NH₃)₃Br₃] + NH₃
(I) Two isomers are produced if the reactant complex ion is a cis-isomer
(II) Two isomers are produced if the reactant complex ion is a trans-isomer
(III) Only one isomer is produced if the reactant complex ion is a trans-isomer
(IV) Only one isomer is produced if the reactant complex ion is a cis – isomer
The correct statements are

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
[3Ca₃ (PO₄)₂.Ca(OH)₂] to

Which of the following compounds will be suitable for Kjeldahl’s method for nitrogen estimation?

The major product of the following reaction is: