$pH$ of a resulting solution prepared by mixing $100 \ mL$ $0.1 \ M$ $HCl$ and $200 \ mL$ $0.05 \ M$ $NaOH$ is

Given,$pH$ of a solution $A$ is $3$ and it is mixed with another solution $B$ having $pH$ $2$. If both are mixed in equal volume,then the resultant $pH$ of the solution will be

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.)

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$BaCO_3 \downarrow + 2HCl \longrightarrow BaCl_2 + CO_2 \uparrow + H_2O$

At $25^{\circ}C$,the dissociation constants of acetic acid and $HCN$ are $1.5 \times 10^{-5}$ and $4.5 \times 10^{-10}$ respectively. What is the equilibrium constant for the following reaction? $(CN^- + CH_3COOH \rightleftharpoons HCN + CH_3COO^-)$

Assign $A, B, C, D$ from the given type of reaction.
$CH_3COOAg(s) + HNO_3(aq) \longrightarrow AgNO_3(aq) + CH_3COOH(aq)$