Buffer system helps to maintain blood $pH$ between .......

Which of the following will not function as a buffer solution?

If the molar concentrations of a base and its conjugate acid are the same, then the $pOH$ of the buffer solution is:

$50 \ mL$ of $0.02 \ M$ $NaOH$ solution is mixed with $50 \ mL$ of $0.06 \ M$ acetic acid solution. The $pH$ of the resulting solution is $......$ ($pK_a$ of acetic acid is $4.76$,$\log 2 = 0.30$).

$50 \ mL$ of $2 \ N$ acetic acid mixed with $10 \ mL$ of $1 \ N$ sodium acetate solution will have an approximate $pH$ of:

The $pOH$ of a basic buffer (e.g.,$NH_4OH/NH_4Cl$) is $5$. If the concentration of the salt is tripled while the concentration of the base remains constant,find the new $pOH$ value. (Given: $\log 3 = 0.48$)