Which base is most suitable to prepare a buffer solution with a pH =11.00 ?

A student is asked to prepare a buffer solution with a pH of 4.00. This can be accomplished by using a solution containing which of the following ?

On diluting a buffer solution, its pH

On diluting a buffer solution, its pH

On diluting a buffer solution, its pH :

Which pair of solutes could be used to prepare an aqueous buffer solution with a pH lt 7 ?

How are buffer solutions prepared ?

Which buffer solution has maximum pH?

How are buffer solutions prepared?