1. Nitric acid is formed by the reaction of nitrogen dioxide with water. 3 NO2(g) + H2O(1) ► NO(g) + 2 HNO3(aq). How many moles of water are needed to react
with 8.4 mol NO2? Show calculation work. (2pts)

a corroding iron, if that's one of your choices

the answer is c i took the test

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.