Chemistry

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:

The reaction in which hybridization of the underlined atom is affected is:

The molecule in which hybrid MOs involve only one d-orbital of the central atom is :

The incorrect statement(s) among (a) - (c) is (are):
(a) W(VI) is more stable than Cr(VI).
(b) in the presence of HCl, permanganate titrations provide satisfactory results.
(c) some lanthanoid oxides can be used as phosphors.

An alkaline earth metal ' M' readily forms water soluble sulphate and water insoluble hydroxide. Its oxide MO is very stable to heat and does not have rock-salt structure. M is: