Ionization constants, ionization of water, pH scale

Phosphoric acid ionizes in three steps with ionization constant values \(K_{a_1}\), \(K_{a_2}\) and \(K_{a_3}\), respectively, while K is the overall ionization constant. Which of the following statements are true?

A. \(\log K = \log K_{a_1} + \log K_{a_2} + \log K_{a_3}\)

B. \(\mathrm{H_3PO_4}\) is a stronger acid than \(\mathrm{H_2PO_4^-}\) and \(\mathrm{HPO_4^{2-}}\).

C. \(K_{a_1} > K_{a_2} > K_{a_3}\)

D. \(K_{a_1} = \frac{K_{a_3}+K_{a_2}}{2}\)

Choose the correct answer from the options given below:

Following solutions were prepared by mixing different volumes of NaOH and HCl of different concentrations :

a. 60 mL \(\frac{M}{10}\) HCl + 40 mL \(\frac{M}{10}\) NaOH

b. 55 mL \(\frac{M}{10}\) HCl + 45 mL \(\frac{M}{10}\) NaOH

c. 75 mL \(\frac{M}{5}\) HCl + 25 mL \(\frac{M}{5}\) NaOH

d. 100 mL \(\frac{M}{10}\) HCl + 100 mL \(\frac{M}{10}\) NaOH

pH of which one of them will be equal to 1 ?

The percentage of pyridine (\(C_5H_5N\)) that forms pyridinium ion (\(C_5H_5N^+H\)) in a \(0.10\,M\) aqueous pyridine solution (\(K_b\) for \(C_5H_5N = 1.7\times10^{-9}\)) is