Question

The dissociation constant of a weak monoacidic base is 10^-5. The pH of its 0.1 M solution will be approximately to to

Answer 1

Hey there!

we know that ,

For a weak acid, [H  +  ]= $\sqrt{ka*c}$

The dissociation constant is 10^  −5  and the concentration is 0.1 M.

Let us now substitute the values in our formula :  

• [H  + ] =  $\sqrt{(1* 10^-5) 0.1}$

​           = $\sqrt{1* 10^-6}$    

                =  1 * $10^{-3}$

• pH = −log[H  +  ]

              = $- log10 ^{-3}$

              = $-(-3)log_{10}$

              =  $3log_{10}$

              = 3                      ($log_{10} = 1$)            

#Hope it helps!