The dissociation constant of acetic acid is $$x\times10^{-5}$$. When 25 mL of 0.2 $$\mathrm{M~CH_3COONa}$$ solution is mixed with 25 mL of 0.02 $$\mathrm{M~CH_3COOH}$$ solution, the pH of the resultant solution is found to be equal to 5. The value of $$x$$ is ____________
If the solubility product of PbS is 8 $$\times$$ 10$$-$$28, then the solubility of PbS in pure water at 298 K is x $$\times$$ 10$$-$$16 mol L$$-$$1. The value of x is __________. (Nearest Integer)
[Given : $$\sqrt2$$ = 1.41]
At $$600 \mathrm{~K}, 2 \mathrm{~mol}$$ of $$\mathrm{NO}$$ are mixed with $$1 \mathrm{~mol}$$ of $$\mathrm{O}_{2}$$.
$$2 \mathrm{NO}_{(\mathrm{g})}+\mathrm{O}_{2}(\mathrm{g}) \rightleftarrows 2 \mathrm{NO}_{2}(\mathrm{g})$$
The reaction occurring as above comes to equilibrium under a total pressure of 1 atm. Analysis of the system shows that $$0.6 \mathrm{~mol}$$ of oxygen are present at equilibrium. The equilibrium constant for the reaction is ________. (Nearest integer)
$$\mathrm{K}_{\mathrm{a}}$$ for butyric acid $$\left(\mathrm{C}_{3} \mathrm{H}_{7} \mathrm{COOH}\right)$$ is $$2 \times 10^{-5}$$. The $$\mathrm{pH}$$ of $$0.2 \,\mathrm{M}$$ solution of butyric acid is __________ $$\times 10^{-1}$$. (Nearest integer)
[Given $$\log 2=0.30$$]