Class 12th

Which one of the following statements is not true?

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

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)

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.

The mechanism of action of "Terfenadine" (Seldane) is :

The one that can exhibit highest paramagnetic behaviour among the following is: gly = glycinato ; bpy = 2,2 '-bipyridine

If 75% of a first order reaction was completed in 90 minutes, 60% of the same reaction would be completed in approximately (in minutes)
(Take: log 2 = 0.30; log 2.5 = 0.40 )