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 $HF$?

The incorrect relation for isohydric solutions is $:-$

Which one of the following statements is correct?

$20 \ mL$,$0.1 \ M \ HA$ $[(K_b)_{A^-} = 10^{-10}]$ is titrated against $0.2 \ M \ NaOH$. Select the correct statement [Given : $\log 2 = 0.3, \log 3 = 0.48$ ]

The pairs of compounds which cannot exist together in aqueous solution are :
$I. NaH_2PO_4$ and $Na_2CO_3$ $II. Na_2CO_3$ and $NaHCO_3$
$III. NaOH$ and $NaH_2PO_4$ $IV. NaHCO_3$ and $NaOH$

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.)