$$300 \mathrm{ml}$$ of an aqueous solution of $$\mathrm{NaOH}$$ with $$\mathrm{pH}$$ value of 10 is mixed with $$200 \mathrm{ml}$$ of an aqueous solution of $$\mathrm{HCl}$$ with a $$\mathrm{pH}$$ value of 4. What will be the $$\mathrm{pH}$$ of the resultant solution at room temperature?
In a $$0.2 \mathrm{~M}$$ aqueous solution, lactic acid is $$6.9 \%$$ dissociated. The value of dissociation constant is
A buffer solution has equal volumes of $$0.1 \mathrm{~M} \mathrm{~NH}_4 \mathrm{OH}$$ and $$0.01 \mathrm{~M} \mathrm{~NH}_4 \mathrm{Cl}$$. The $$\mathrm{pK}_b$$ of the base is 5. The $$\mathrm{pH}$$ is
What would be the volume of water required to dissolve $$0.2 \mathrm{~g}$$ of $$\mathrm{PbCl}_2$$ of molar mass $$278 \mathrm{~g} / \mathrm{mol}$$ to prepare a saturated solution of the salt? $$(\mathrm{K}_{\mathrm{SP}}$$ of $$\mathrm{PbCl}_2=3.2 \times 10^{-8})$$