$A$ 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?

When dilute $H_2SO_4$ is added to an aqueous solution of potassium chromate,the yellow color of the solution changes to orange. This indicates that .....

The percentage of ionization of $1 \ L$ of $x \ M$ acetic acid is $4.242$ and is called solution "$A$". The percentage of ionization of $1 \ L$ of $y \ M$ acetic acid is $3$ and is called solution "$B$". Solution "$A$" is mixed with solution "$B$". What is the concentration of acetic acid in the resultant solution (in $M$)? $\left(K_{a} \text{ of acetic acid } = 1.8 \times 10^{-5}\right)$

What will be the change in acidity if
$(i)$ $CuSO_4$ is added in saturated $(NH_4)_2SO_4$ solution
$(ii)$ $SbF_5$ is added in anhydrous $HF$?

Formic acid $(HCOOH)$ is a weak acid and hydrochloric acid $(HCl)$ is a strong acid. It follows that the:

$0.01 \ M \ HA(aq.)$ is $2 \%$ ionized,$[OH^{-}]$ of solution is :-