Sum of $$\pi$$-bonds present in peroxodisulphuric acid and pyrosulphuric acid is ___________

The number of units, which are used to express concentration of solutions from the following is _________

Mass percent, Mole, Mole fraction, Molarity, ppm, Molality

The total pressure observed by mixing two liquids A and B is 350 mm Hg when their mole fractions are 0.7 and 0.3 respectively.

The total pressure becomes 410 mm Hg if the mole fractions are changed to 0.2 and 0.8 respectively for A and B. The vapour pressure of pure A is __________ mm Hg. (Nearest integer)

Consider the liquids and solutions behave ideally.

If the pKa of lactic acid is 5, then the pH of 0.005 M calcium lactate solution at 25$$^\circ$$C is ___________ $$\times$$ 10$$^{-1}$$ (Nearest integer)