d. Distillation: Distill and collect 200 ml distillate below the surface of 50 ml boric acid solution. Use plain boric acid solution when the ammonia is to be determined by nesslerization and use indicating boric acid for a titrimetric finish. Extend the tip of the condenser well below the level of boric acid solution and do not allow the temperature in the condenser to rise above 29 C Lower the collected distillate free of contact with the delivery tube and continue distillation during the last minute or two to cleanse the condenser.