Describe how chlorine gas is prepared in the laboratory without heating. How does chlorine react with (a) excess of ammonia and (b) hot sodium hydroxide solution? Explain with equation.

Explanation

Preparation of Chlorine Chlorine can be prepared by heating manganese dioxide with conc. HCI.
`MnO_(2)+4HCl toMnCl_(2)+Cl_(2)+2H_(2)O`
Important Points In the reaction, a mixture of NaCl and conc. `H_(2)SO_(4)` can be used in place of HCl,
`4NaCl+MnO_(2)+4H_(2)SO_(4)toMnCl_(2)+4NaHSO_(4)+2H_(2)O+Cl_(2)`
It can also be obtained by the action of HCI on potassium permanganate.
`2KMnO_(4)+16HCl to2KCl+2MnCl_(2)+8H_(2)O+5Cl_(2)`
Manufacture of Chlorine Chlorine can be manufactured by the following two processes
(i) Deacon.s Process It can be manufactured by Deacon.s process in which oxidation of HCl gas is done by atmospheric `O_(2)` in the presence of `CuCl_(2)` (catalyst) at 723 K.
`4HCl+O_(2)overset(CuCl_(2))underset(723K)(to)2Cl_(2)+2H_(2)O`
(ii) Electrolytic Process Chlorine can be obtained by the electrolysis of concentrated solution of NaCl (brine).
`2NaCl+2H_(2)Oto2NaOH+underset("At anode")(Cl_(2)(g))+underset("At anode")(H_(2)(g))`
(a) Chlorine gives nitrogen and ammonium chloride with excess ammonia.
`underset("Excess")(8NH_(3))+3Cl_(2)to6NH_(4)Cl+N_(2)`
(b) Chlorine reacts with hot sodium hydroxide solution in the following manner.
`underset("Hot and conc.")(6NaOH+3Cl_(2))to5NaCl+underset("Sodium chlorate")(NaClO_(3)+3H_(2)O)`