The hydrolysis constants of salts $M_1X$ and $M_2X$ formed from a strong acid and weak bases are $10^{-7}$ and $10^{-4}$ respectively. For base $M_3OH$,$K_b = 10^{-4}$. The decreasing order of basic strength is:

Calculate the $pH$ of the resultant mixtures:
$(a)$ $10 \, mL$ of $0.2 \, M \, Ca(OH)_{2} + 25 \, mL$ of $0.1 \, M \, HCl$
$(b)$ $10 \, mL$ of $0.01 \, M \, H_{2}SO_{4} + 10 \, mL$ of $0.01 \, M \, Ca(OH)_{2}$
$(c)$ $10 \, mL$ of $0.1 \, M \, H_{2}SO_{4} + 10 \, mL$ of $0.1 \, M \, KOH$

When $10 \, mL$ of $0.1 \, M$ acetic acid $(pK_a = 5.0)$ is titrated against $10 \, mL$ of $0.1 \, M$ ammonia solution $(pK_b = 5.0)$,the equivalence point occurs at $pH$:

Order of solubility of solid $AgCl_{(s)}$ in given cases.
$(i)$ In pure water
$(ii)$ In presence of $0.1 \ M$ $AgNO_3$
$(iii)$ In presence of $2 \ M$ $aq.$ solution of $KCN$
$(iv)$ In presence of $1 \ M$ $aq.$ solution of $Ca(CN)_2$
$(v)$ In presence of $2 \ M$ $aq.$ solution of $NH_3$
(Assuming $100 \%$ dissociation of $AgNO_3$,$KCN$ and $Ca(CN)_2$ and complex formation with $NH_3$ and $CN^{-}$ will take place.)

The $pH$ value of a decinormal solution of $NH_4OH$ which is $20\%$ ionised,is

During the titration of acetic acid with an aqueous $NaOH$ solution,the neutralization graph shows a vertical line. This line indicates: