The species present in solution when $CO_2$ is dissolved in water are

Calculate the $pH$ of a mixed solution containing $10 \ mL$ of $0.2 \ M$ $Ca(OH)_2$ and $25 \ mL$ of $0.1 \ M$ $HCl$.

The dissociation constant of a certain weak acid is $1.0 \times 10^{-4}$. What is the equilibrium constant for its reaction with a strong base?

$A$ $0.1 \ N$ solution of an acid at room temperature has a degree of ionisation $0.1$. The concentration of $OH^{-}$ would be

The plot of $pH$-metric titration of weak base $NH_4OH$ vs strong acid $HCl$ looks like:

$A$ 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?