I believe the answer is the first one you listed,
Hope this helps..
One reasonable plan would be to wear a face mask or surgical
mask. Take note that your surgical mask contains two sides – the white side and the
blue side. Since the main purpose of your mask usage is to prevent yourself
from inhaling too much bad air, the blue side of the mask should be the one
touching your skin. This is because the white side of your mask helps you
prevent from coming in contact with toxins that may come from the smog.
See attached image for most common formula of sulfuric acid.
2NH3 is equivalent to N2 + H6 since the 2 at the beginning gets distributed to both atoms. Knowing this you can rewite the equation as
H2 + N2 = H6 + N2
The N2 can cancel out leaving
H2 = H6
You now have to ask ‘2 times what equals 6?’ The answer is obviously 3 at this point.
Answer: C. 3
