I think the answer would be b because your throat is reacting to the cough?
Answer:Since there is virtually nothing in space to scatter or re-radiate the light to our eye, we see no part of the light and the sky appears to be black.
Explanation:
Answer : The mole fraction of NaCl in a mixture is, 0.360
Explanation : Given,
Moles of
= 7.21 mole
Moles of
= 9.37 mole
Moles of
= 3.42 mole
Now we have to calculate the mole fraction of
.

Now put all the given values in this formula, we get:

Therefore, the mole fraction of NaCl in a mixture is, 0.360
Carbon dioxide (CO2)
Argon (Ar)
Hydrogen (H)
Helium (He)