Question 8

buffer solutions:

keep the ph of the solution constant even when small amounts of acid or base are added

resist changes in ph when small amounts of acid or base are added

are not used up in buffer reactions and can keep reacting to adjust the ph indefinitely

have no practical uses outside of laboratory conditions

B

Explanation:

I would go with B b/c C and D are wrong. The reason C is wrong is that buffers do get used up after a while so it wont be able to react indefinitely to maintain the pH and the reason D is wrong is that there are thousands of uses for buffer ranging from your own human body to thousands and thousands of things.

In my opinion, A is not necessarily wrong because buffer's job is to keep the pH of the solution relatively constant (up to some point), but I think B is still the best answer because it describes the actual function of buffer which is to resist pH.

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).