Given relevent chemical equations for the preparation of
a.HBr from potassium bromide.
b. Bleaching powder from slaked lime.
c. `NaClO_(3)` from sodim choride.

Explanation

(a) Chlorine is obtained fron sodium chloride by the electrolysis of its aqueous solution.

At cathode: `H^(o+)+e^(Ө)toH`
`2H to H_(2)uarr`
At anode: `Cl^(Theta) to Cl+e^(Theta)`
`2Cl to Cl_(2)uarr`.
(b) Kelp i.e. ash of sea-weeds is extracted with water, the suphates and chlorides of `Na` and `K` present in it are removed by crystallisation. The mother liquor is heated with `MnO_(2)` and conc. `H_(2)SO_(4)`. The iodine vapours are collected in earthen jars.
`2NaI+3H_(2)SO_(4)+MnO_(2)to 2NaHSO_(4)+MnSO_(4)+2H_(2)O+I_(2)`
(c) `HBr` is prepared by heating `KBr` with conc. phosphoric acid.
`3KBr+H_(3)PO_(4) to K_(3)PO_(4)+3HBr`
(d) Slaked lime `Ca(OH)_(2)` is treated with chlorine gas by slowly moving forward dry slake lime in a series of shelves provided with rotating rakes.
`Ca(OH_(2))+Cl_(2) to CaOCl_(2).H_(2)O`
(e) sodium chlorate is first obtained by carrying electrolysis of hot concentrated solution of sodium chloride in an electorlytic cell.
`underset("Solution")(NaCl) overset("Electrolysis")(rarr) underset("Cathode")(H_2)+underset("Anode")(Cl_(2))`
`Na^(o+)+overset(Theta)(O)H rarr NaOH`
`Cl_(2)` reacts with `NaOH` forming `NaClO_(3)`
`6NaOH+3Cl_(2) rarr 5NaCl + NaClO_(3)+3H_(2)O`
`KCl` is added to form sparingly soluble `KClO_(3)`
`NaClO_(3)+KCl rarr KClO_(3)+NaCl`.