Question

${10}^{-6}M$ NaOH is diluted $100$ times. The pH of the diluted base is

• A. between $5and6$
• B. between $6and7$
• C. between $10and11$
• D. between $7and8$

Answer 1

The correct option is D between $7and8$

The Definition of pH

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

pH is defined as the negative logarithm of concentration of protons $\left(H^{+}\right)$ in a solution.

the concentration of H+ ions is ${10}^{-6}$ moles/ltr.

So, when you dilute an acid so that its molarity is ${10}^{-}8$, the total concentration of H+ ions in the solution is still greater than ${10}^{-7}$ which is basically the base.

Hence, you get the pH of a very dilute acid to be always less than 8 and greater than 7.