Question

How is it possible to eat acidic things without changing your blood pH? Select all that applyBlood contains enzymes that neutralize acidsBlood can absorbed small amounts of acids or bases without harmful effectsBlood blocks acids and bases from entering the bloodstreamBlood contains buffers to help neutralize acids

Answer 1

Step 1 - Understanding how blood keeps its pH roughly constant

In our blood there's a buffering system. A buffering system consists of a group of molecules which can undergo reactions in presence of acids or bases, quickly consuming them.

When a solution is buffered, its pH can remain constant as long as we add small quantities of acid or bases. In our blood, the buffering involves the anion bicarbonate, HCO3(-), as well as carbonic acid, H2CO3.

In the presence of acids, HCO3(-) quickly neutralizes it:

`\text{HCO}^-_3+H^+\to H_2CO3`

In the presence of bases, it is H2CO3 who acts:

`H_2CO_3+OH^-\to H_2O+HCO^-_3`

Note that bicarbonate restitues carbonic acid, while carbonic acid restitutes bicarbonate. This way our blood remains its pH almost intact.

Step 2 - Choosing the right alternatives

The correct alternatives, based on what we have seen, are:

Blood can absorb small amounts of acids or bases without harmful effects

Blood contains buffers to help neutralize acids