The parameter pH is a measure of the substance's acidity or basicity. It is quantitatively equal to the negative logarithm of the concentration of H+ ions. So, the lower the pH, the more acidic the substance, Otherwise, the higher the pH the more basic the substance. The pH range runs from 1 to 14, with 7 being neutral.
So, if we are asked to distinguish which of those have the lowest pH, we have to know the moles of H+ ions. Since all of them have a concentration of 0.1 M, concentration is not a factor. Thus, we just have to identify the strongest acid among the list. That is easy to answer because you only have to remember 7 strong acid occurring in nature: HCl, H₂SO₄, HNO₃, HClO₄, HClO₃, HBr, and HI. Since only HNO₃ is included in the list among the choices, the answer would be letter D.
Answer:

Explanation:
1. Calculate the mass of each element

2. Calculate the moles of each element

3. Calculate the molar ratios
Divide all moles by the smallest number of moles.

4. Round the ratios to the nearest integer
C:H = 1:2
5. Write the empirical formula
The empirical formula is 
Metalloids show both metal and non metal properties
when she reaches for the cup that is somatic nervous system. when she begins to cough
Molecular formula is CIO3