$A$ buffer solution has equal volumes of $0.2 \ M \ NH_4OH$ and $0.02 \ M \ NH_4Cl$. The $pK_b$ of the base is $5$. The $pH$ is

Which of the following does not act as a buffer solution?

One litre of an aqueous solution contains $0.15 \ mol$ of $CH_3COOH$ $(pK_a = 4.8)$ and $0.15 \ mol$ of $CH_3COONa$. After the addition of $0.05 \ mol$ of solid $NaOH$ to this solution,the $pH$ will be:

Buffer solutions have constant acidity and alkalinity because

The principal buffer present in human blood is:

What is the value of $pOH$ if a buffer solution is prepared by mixing equal volumes of $0.4 \ M$ $NH_4OH$ and $0.5 \ M$ $NH_4Cl$ solutions? $(pK_b = 4.730)$