Calculate the molar solubility of $AgCl$ at $25\,^oC$ in $3.0\ M\ NH_3$ ($K_{sp}$ of $AgCl = 2.0 \times 10^{-10}$,$K_f$ of $[Ag(NH_3)_2]^+ = 1.25 \times 10^7$) (in $M$)

$A$ sample of $MgCO_3$ is dissolved in dil. $HCl$ and the solution is neutralized with ammonia and buffered with $NH_4Cl / NH_4OH$. Disodium hydrogen phosphate reagent is added to the resulting solution. $A$ white precipitate is formed. What is the formula of the precipitate?

The dissociation constant of pure water at $18\,^oC$ will be .......... (Degree of dissociation of pure water at $18\,^oC = 1.8 \times 10^{-9}$)

The $pH$ of a solution obtained by mixing $50 \, mL$ of $1 \, M \, HCl$ and $30 \, mL$ of $1 \, M \, NaOH$ is $x \times 10^{-4}$. The value of $x$ is ...... . (Nearest integer) $[\log 2.5 = 0.3979]$

In which of the following equations will $\alpha_1$ or $\alpha_2$ be higher?
$(i) \, NH_4OH + H_2O \rightarrow \alpha_1$
$(ii) \, NH_4OH + D_2O \rightarrow \alpha_2$

Equal volumes of three acid solutions with $pH$ values of $3, 4,$ and $5$ are mixed. What will be the concentration of $H^+$ ions in the resulting mixture?