An analyst wants to convert $$1 \mathrm{~L} \mathrm{~HCl}$$ of $$\mathrm{pH}=1$$ to a solution of $$\mathrm{HCl}$$ of $$\mathrm{pH} ~2$$. The volume of water needed to do this dilution is __________ $$\mathrm{mL}$$. (Nearest integer)
The solubility product of $$\mathrm{BaSO}_{4}$$ is $$1 \times 10^{-10}$$ at $$298 \mathrm{~K}$$. The solubility of $$\mathrm{BaSO}_{4}$$ in $$0.1 ~\mathrm{M} ~\mathrm{K}_{2} \mathrm{SO}_{4}(\mathrm{aq})$$ solution is ___________ $$\times 10^{-9} \mathrm{~g} \mathrm{~L}^{-1}$$ (nearest integer).
Given: Molar mass of $$\mathrm{BaSO}_{4}$$ is $$233 \mathrm{~g} \mathrm{~mol}^{-1}$$
The titration curve of weak acid vs. strong base with phenolphthalein as indictor) is shown below. The $$\mathrm{K}_{\text {phenolphthalein }}=4 \times 10^{-10}$$.
Given: $$\log 2=0.3$$
The number of following statement/s which is/are correct about phenolphthalein is ___________
A. It can be used as an indicator for the titration of weak acid with weak base.
B. It begins to change colour at $$\mathrm{pH}=8.4$$
C. It is a weak organic base
D. It is colourless in acidic medium
(Given mass of $\mathrm{Ag}$ is $107.9 \mathrm{~g} \mathrm{~mol}^{-1}$ and mass of $\mathrm{Cl}$ is $35.5 \mathrm{~g} \mathrm{~mol}^{-1}$ )