A. The products of the change are different from the starting
substances.
<u>Explanation:</u>
Whenever there is a physical change it may just affect the phase change but the properties remains the same. Whenever there is an occurrence of a chemical change, it was indicated by some of these things such as,
- The products are exactly different from the products.
- Chemical properties of these reactants are entirely different from that of the products.
- Chemical composition as well as the physical properties of the reactants and the products will change
The molarity of the stock solution is 1.25 M.
<u>Explanation:</u>
We have to find the molarity of the stock solution using the law of volumetric analysis as,
V1M1 = V2M2
V1 = 150 ml
M1 = 0.5 M
V2 = 60 ml
M2 = ?
The above equation can be rearranged to get M2 as,
M2 = 
Plugin the values as,
M2 = 
= 1.25 M
So the molarity of the stock solution is 1.25 M.
It is
<span>b. strong acid vs. weak base.</span>