Which of the following sentence best describes a buffer? a. buffers resist change in ph of solutions by neutralizing excess acid or base. b. buffers change the ph of solutions by increasing acidity or basicity of solutions. c. buffers change the ph of solutions by decreasing acidity or basicity of solutions.

Answer : The correct option is, (A) Buffers resist change in pH of solutions by neutralizing excess acid or base.

Explanation :

Buffer : It is a solution that prevent any changes in the pH of the solution on the addition of an acidic and basic components.

Or, it is a solution that maintain the pH of the solution by adding the small amount of acid or a base.

There are two types of buffer which are acidic buffer and basic buffer.

Acidic buffer : It is the solution that have the pH less than 7 and it contains weak acid and its salt. For example : Acetic acid (weak acid) and sodium acetate (salt).

Basic buffer : It is the solution that have the pH more than 7 and it contains weak base and its salt. For example : Ammonia (weak base) and ammonium chloride (salt).

Hence, the correct option is, (A) Buffers resist change in pH of solutions by neutralizing excess acid or base.

answer: the blood-brain barrier is a layer of specialized membranes and cell processes designed to keep undesirable substances from passing from the bloodstream into the precious tissues of the brain. while the blood-brain barrier does keep most bad things out of the central nervous system, it is not impermeable.

explanation:

the answer is d. chordata