Question

$pH$ of human blood is $7.4$ . Then $H^{+}$ concentration will be:

• A. $4\times 10^{-8}$
• B. $2\times 10^{-8}$
• C. $4\times 10^{-4}$
• D. $2\times 10^{-4}$

Answer 1

Answer: (A)

$pH=-{\log }_{10}\left[H^{+}\right]$
$7.4=-{\log }_{10}\left[H^{+}\right]$
${\log }_{10}\left[H^{+}\right]=-7.4$
$\left[H^{+}\right]=10^{-7.4}$
$=10^{-8}\times 10^{0.6}$
$=10^{-8}\times$ anti $\log 10^{0.6}=10^{-8}\times 4$
$\left[H^{+}\right]=4\times 10^{-8}$