The following pictures represent aqueous solutions of three acids HA (A = X,Y,or Z),with water molecules omitted for clarity.Unshaded spheres represent hydrogen atoms or ions and gray spheres represent A atoms or ions.Which of the three is the strongest acid,and which is the weakest?
A)HX is the strongest acid and HY is the weakest acid.
B)HY is the strongest acid and HX is the weakest acid.
C)HY is the strongest acid and HZ is the weakest acid.
D)HZ is the strongest acid and HY is the weakest acid.

Question

The following pictures represent aqueous solutions of three acids HA (A = X,Y,or Z),with water molecules omitted for clarity.Unshaded spheres represent hydrogen atoms or ions and gray spheres represent A atoms or ions.Which of the three is the strongest acid,and which is the weakest? 
A)HX is the strongest acid and HY is the weakest acid. 
B)HY is the strongest acid and HX is the weakest acid. 
C)HY is the strongest acid and HZ is the weakest acid. 
D)HZ is the strongest acid and HY is the weakest acid.

Quizplus · Accepted Answer

In order to determine the strength of an acid, we look at its ability to donate protons (H+ ions). The more readily an acid donates protons, the stronger it is. In the given solutions, HY has the most dispersed negative charge around the A atom, making it the most polarizable and therefore the easiest to donate a proton. Thus, HY is the strongest acid. HZ has the most electronegative A atom, making it the least likely to donate a proton. Therefore, HZ is the weakest acid. HX falls in between, making it a moderately strong acid. Therefore, the correct answer is C.

The Following Pictures Represent Aqueous Solutions of Three Acids HA