When a base is added to a buffered solution, the buffer will .
a. accept water molecules
b. donate OH ions
c. form covalent bonds with the base
d. donate H+ ions

d. donate H+ ions

Explanation:

Mixture of weak acid and its conjugate base or mixture of weak base and its conjugate acid resist the change in pH of the solution when acids or bases are added to them. Such solutions which resist the change in pH on adding acids or bases are called buffer solution.

Buffer solution reverse the effect of addition of acids and bases by neutralizing them.  

So, if base is added, it combines with H+ ions released by buffer solution to form water. Therefore, among the given the correct option is d, donate H+ ions.

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally