Question

Which is the best choice for preparing a buffer with a pH of 7.00? Select one:

a. Adding strong base to a solution of hydrocyanic acid

b. Adding strong base to a solution of hypochlorous acid

c. Adding strong base to a solution of formic acid

d. Pure water

e. Adding strong base to a solution of phenol

Answer 1

D) pure watre is correct option

AS we have to prepare a buffer solution of pH = 7.00

in the above options ( hydrocyanic acid , hypochlorous acid , formic acid, phenol )

all are weak base and we are treating them to a strong base so we will never get a pH of = 7 ,

we get pH>7 ( basic buffer )

but when we use pure water ( with out impurities either acidic or basic ) we can expect that the pH of

pure water =7 , which is best choice of preparing buffer whose pH = 7.00