Chemistry

For a reaction,
4M(s) + nO₂(g) → 2M₂Oₙ(s),
the free energy change is plotted as a function of temperature. The temperature below which the oxide is stable could be inferred from the plot as the point at which

At 20.0 mL solution containing 0.2 g impure H2O2 reacts completely with 0.316 g of KMnO4 in acid solution. The purity of H2O2 (in %) is (mol. wt. of H2O2 = 34; mol. wt. of KMnO4 = 158 )

The osmotic pressure of a solution of NaCl is 0.10 atm and that of a glucose solution is 0.20 atm. The osmotic pressure of a solution formed by mixing 1 L of the sodium chloride solution with 2 L of the glucose solution is x * 10⁻³ atm. x is (nearest integer)

A 100 mL solution was made by adding 1.43 g of Na₂CO₃ · xH₂O. The normality of the solution is 0.1 N. The value of x is (The atomic mass of Na is 23 g/mol )

The number of chiral centres present in threonine is

Consider the following equations :
2Fe²⁺ + H₂O₂ → xA + yB (in basic medium)
2MnO₄⁻ + 6H⁺ + 5H₂O₂ → x'C + y'D + z'E (in acidic medium)
The sum of the stoichiometric coefficients x, y, x', y' and z' for products A, B, C, D and E, respectively, is

The number of chiral centres present in [B] is

The number of molecules with energy greater than the threshold energy for a reaction increases five fold by a rise of temperature from 27°C to 42°C. Its energy of activation in J/mol is (Take in 5 = 1.6094; R = 8.314 J mol⁻¹ K⁻¹)

Five moles of an ideal gas at 1 bar and 298 K is expanded into vacuum to double the volume. The work done is :

The shortest wavelength of H atom in the Lyman series is λ₁. The longest wavelength in the Balmer Series of H⁺ is: