How many times of the acetic acid concentration, acetate salt should be added to a given acetic acid solution to obtain a solution of pH = 7.0 (`K_a` for `CH_3COOH=1.8xx10^(-5)` ) .

Explanation

Suppose the concentration of the acetate salt added is x times the concentration of acetic acid solution to obtain `pH=7. "Then " [CH_(3)CO O^(-)]=x xx [CH_(3)CO OH] :. ([CH_(3)CO O^(-)])/([CH_(3)CO OH])=x`
Now, for acid buffer, `pH = pK_(a) + log .(["Salt"])/("Acid"])`
`:. 7 = - log (1.8xx10^(-5))+ log x or 7 = 4.76+ log x or log x = 2.24 or x = 1.73 xx 10^(2) = 173` times