\(pH =\) \( - \frac{1}{2}[\log {K_a} + \log {K_w} - \log {K_b}]\)
\( = - \frac{1}{2}[ - 5 + \log (1 \times {10^{ - 14}}) - ( - 5)]\)
\( = - \frac{1}{2}[ - 5 - 14 + 5] = - \frac{1}{2}( - 14) = 7\)
($BaCO_3$ માટે $K_{sp}$ =$ 5 .1 \times 10^{-9}$)