If I added 50 mL of a 1.0 M HCIO2 solution to 50 mL of a 1.0 M NaOH
solution, what would the pH of the resulting solution be? *

pH=7

Explanation:

0.05 L*1.0M= 0.05 mol HClO2  and 0.05 mol NaOH      

HClO2 +     NaOH ---> NaClO2 + H2O

0.05 mol     0.05 mol

As we can see acid and base  react completely,  solution will be neutral, so pH =7

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

10 years is the answer