67.In the intense heat of welding,even nitrogen can be oxidized.
68.In the intense heat of welding,even argon can be oxidized.
69.In the intense heat of welding,even helium can be oxidized.
70.According to Sax,exposure to NOx in which of the following ranges results in the air hunger,cyanosis,loss of consciousness,and final death?
A)25 to 50 ppm
B)60 to 150 ppm
C)200 to 500 ppm
D)1 to 2 per cent