In which of the following does a buffer solution play an important role?

$50 \ mL$ 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 $4.76$,$\log 2 = 0.30$).

An acidic buffer is obtained on mixing

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

Which of the following would produce a buffer solution when mixed in equal volumes?

When $0.02 \ mol$ of $NaOH$ is added to $1 \ L$ of a buffer solution,its $pH$ changes from $5.75$ to $5.80$. What is the buffer capacity of the solution?