Grease is nonpolar. It is made up of lengthy hydrocarbon chains attached to glycerol (triacylglycerols). Because of this property, nonpolar solvents, such as tetrachloroethylene, can get grease out of clothes. This solvent acts by dissolving the grease, thereby removing it from clothes without leaving any residue.
Question 1:
(a) Sulfurous acid: H2SO3
Sulfuric acid: H2SO4
(b) Nitrous acid: H2NO2
Nitric acid: H2NO3
Question 2:
To calculate the pH, based on concentration of H+ ions, there is one formula:

So the pH of this solution is

(the solution is basic).
Answer:

Explanation:
You look at the type of atom and their electronegativity difference.
If ΔEN <1.6, covalent; if ΔEN >1.6, ionic
Ar/Xe: Noble gases; no reaction
F/Cs: Non-metal + metal; ΔEN = |3.98 – 0.79| = 3.19; Ionic
N/Br: Two nonmetals; ΔEN = |3.04 - 2.98| = 0.
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