A Compound on analysis gave Na = 14.31% S = 9.97% H = 6.22% and 0 = 69.5%.
Calculate the molecular formula of the compound if all the hydrogen in the compound is present in combination with oxygen as a water of crystallization. (molecular mass of the compound is 322).

What is the de Broglie wave length of an electron, which is accelerated from the rest, through a potential difference of 100 V ?

What is screening effect? Briefly give the basis for pauling's scale of electronegativity.

A group-1 metal (A) which is present in common salt reacts with (B) to give compound (C) in which hydrogen is present in –1 oxidation state. (B) on reaction with a gas (C) to give universal solvent (D). The compound (D) on reacts with (A) to give (E), a strong base. Identify A, B, C, D and E. Explain the reactions.

Describe briefly the biological Importance of Calcium and magnesium.

Write the Van der Waals equation for a real gas. Explain the correction term for pressure and volume.

Calculate the enthalpy change for the reaction
Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂ from the following data.
2Fe +\(\frac{3}{2}\)O₂ ⟶ Fe₂O₃; ΔH = -741 kJ
C +\(\frac{1}{2}\)O₂ ⟶ CO; ΔH = -137 kJ 
C + O₂ ⟶ CO₂; ΔH = - 394.5 kJ

1 mol of CH₄, 1 mole of CS₂ and 2 mol of H₂S are 2 mol of H₂ are mixed in a 500 ml flask. The equilibrium constant for the reaction K_C = 4 x 10^–2 mol² lit^–2. In which direction will the reaction proceed to reach equilibrium ?

Henry’s law constant for solubility of methane in benzene is 4.2 x 10^-5 mm Hg at a particular constant temperature At this temperature.
Calculate the solubility of methane at
i) 750 mm Hg
ii) 840 mm Hg

Identify the compound A, B, C and D in the following series of reactions

How is acid rain formed ? Explain its effect