It is false that:
a) Leak testing by soap and water is safe
b) Halide torch detector is not reliable if the air space is contaminated with refrigerant
c) Leak testing may be done by N2 or CO2
d) Ammonia vapor leak will change the color of the litmus paper to an orange hue
e) Electronic leak detector can pick up even a minute amount of refrigerant leak
Answer: D