Product Short Description: RXSOL TK5 addition will change ORANGE / light reddish colour of sample water. Its reagent comply with TK 6 Product Description: PROCEDURE for test ( STEP WISE ): Measure 1 ml of SAMPLE WATER in graduated TEST TUBE / CYLINDER , with the help of syringe / pippet and diluted with Distilled Water up to 10 ml. Add 1-2 drops of RXSOL TK5 and mix with the stirring rod , to obtain ORANGE / light reddish colour. Add RXSOL TK6 drop by drop , mixing with the stirring rod until For endpoint ORANGE to BLUE / GREENISH colour just appears / develop. Each DROPS is equivalent to 50 PPM of NO2 CALCULATION : 50 X Number of DROPS of TK6