Question

100ml of the 0.1 M NaOH is added to 100 ml of a 0.2 m ch3cooh solution. The pH of resulting solution will be (LA for ch3cooh = 1.8 x 10-5)

Answer 1

pH=8.87

Explanation:

The pH of the solution by mixing 100ml. of 0.2 M $CH_3COOH$,and 100ml of 0.1 M NaOH will by using formula,

7=1/2 PKa + 1/2 log C

C= $\frac{Total moles formed}{Total Volume}$

  =$\frac{0.2}{10}$

 =0.02

Now,

$CH_3COOH+ NaOH\to\ CH_3COOH + H_2O$

$CH_3COOH$ is partially dissociate ,NaOH is completely dissociate,

C=$\frac{0.02}{0.2}$

 =0.1

Now,using formula to calculate pH

pH= 7+1/2$PK_a$+1/2 logC

   = 7+$\frac{1}{2}[4.74+ log 0.1]$

   = 7+$\frac{1}{2}[4.74+(-1)]$

  = 7+$\frac{1}{2}[3.74]$

  =7+1.87

 =8.87

pH=8.87