Question

In the sample of soft drink, the concentration of $H^{+}$ ion is $3.8\times {10}^{-3}M$. Its pH is:

• A. $2$
• B. $2.42$
• C. $3$
• D. $3.42$

Answer 1

The correct option is B $2.42$

$pH=-\log \left[H^{+}\right]$

$pH=-\log [3.8\times {10}^{-3}]$

$pH=-(-3\log 10+\log 3.8)$

$=+3-0.5798=2.4202\approx 2.42$