Question

chlorine gas is pssed through hot and concentrated solution of sodium hydroxide

Answer 1

Cl2 + 2 NaOH ==> NaCl + NaOCl + H2O for cold NaOH 

3 Cl2 + 6 NaOH ==> 5 NaCl + NaClO3 + 3 H2O for hot NaOH 

Chlorine is oxidized much more strongly with hot NaOH than cold 
Cl2 starts neutral and becomes +1 in NaOCl 
Cl2 starts neutral and becomes +5 in NaClO3 
the heat and concentrated NaOH are stronger oxidizing agents than cold dilute NaOH

Answer 2

 Cl2 + 2 NaOH ==> NaCl + NaOCl + H2O for cold NaOH 

3 Cl2 + 6 NaOH ==> 5 NaCl + NaClO3 + 3 H2O for hot NaOH 

Chlorine is oxidized much more strongly with hot NaOH than cold 
Cl2 starts neutral and becomes +1 in NaOCl 
Cl2 starts neutral and becomes +5 in NaClO3 
the heat and concentrated NaOH are stronger oxidizing agents than cold dilute NaOH