In a glass tube of 1 m length and uniform cross section, NH (g) from one end and BF (g) from the other end are sent at a time. The distance from the ammonia end where the addition compound, BF, NH; will first form is (B = 11; F = 19) (a) 66.67 cm (b) 33.33 cm (c) 50.00 cm (d) 60.00 cm