Which of the following is TRUE? A) An effective buffer has a [base]/[acid] ratio in the range of 10 - 100. B) A buffer is most resistant to pH change when [acid] = [conjugate base] C) An effective buffer has very small absolute concentrations of acid and conjugate base. D) A buffer cannot be destroyed by adding too much strong base. It can only be destroyed by adding too much strong acid. E) None of the above is true.

B is true.

Explanation:

A buffer is the mixture of a weak acid with its conjugate base or vice versa.

An effective buffer has a pH  of pKa ± 1. Using H-H formula:

pH = pKa + log [base] / [acid]

1 = log [base] / [acid]

10 = [base] / [acid]

Or

-1 = log [base] / [acid]

0.1 = [base] / [acid]

In other words, the 1 [base] / [acid] ratio in an effective buffer is between 0.1-100. A IS FALSE

The buffer is most resistant to pH change when pH = pKa. Using H-H formula:

pH = pKa + log [base] / [acid]

0 = log [base] / [acid]

1 = [base] / [acid]

In other words, when [base] = [acid] B IS TRUE

In a buffer, an effective buffer must have a higher concentration of pair acid conjugate base. Thus C IS FALSE

The addition of strong base produce conjugate base decreasing concentration of acid. Too much strong base produce a big  [base] / [acid] ratio destroying buffer. D IS FALSE

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.

the answer is symmetrical : )