<span>The pH scale is a logarithmic scale. Each change of 1 unit in pH represents a 10-fold change in hydrogen ion concentration. As the pH gets smaller the hydrogen ion concentration gets larger. Since you have gone from pH 5 to pH 3 there is a 100-fold increase in [H+].
For pH = 5; [H+] = antilog 10^-pH = 1.0 x 10^-5 M
For pH = 3; [H+] = antilog 10^-pH = 1.0 x 10^-3 M
(1.0 x 10^-3)/(1.0 x 10^-5) = 1.0 x 10^2 hope this helps</span>
(3) empirical, molecular, structural is the correct answer.
Group (1) shows the little factors to form substances and compounds. Group (2) shows the types of elements. Group (4) shows the types of chemical reaction.
Hope this would help~
What are you supposed to do
exactly?