Class 11th

In Duma's method of estimation of nitrogen, 0.1840 g of an organic compound gave 30 mL of nitrogen collected at 287 K and 758 mm of Hg pressure. The percentage composition of nitrogen in the compound is __________. (Round off to the nearest integer).
[Given: Aqueous tension at 287K = 14 mm of Hg]

The number of orbitals with n=5, m? = +2 is __________

Sulphurous acid (H₂SO₃) has Ka₁ = 1.7 * 10⁻² and Ka₂ = 6.4 * 10⁻⁸ . The pH of 0.588 M H₂SO₃ is __________.

The exact volumes of 1 M NaOH solution required to neutralize 50 mL of 1M H₃PO₃ solution and 100 mL of 2M H₃PO₂ solution respectively, are

Match List – I with List – II

The correct statement about H₂O₂ are:
(A) Used in the treatment of effluents.
(B) Used as both oxidizing and reducing agents
(C) The two hydroxyl groups lie in the same plane.
(D) Miscible with water.
Choose the correct answer from the options given below:

The gas phase reaction 2A(g) ? A?(g) At 400 K has ΔG° = +25.2 kJ mol?¹.
The equilibrium constant K? for this reaction is ________ *10?². (Round off to the nearest integer).
[ Use: R = 8.3 J mol?¹ K?¹, In10 = 2.3, log? 2 = 0.30, 1atm = 1 bar]
[antilog (-0.3) = 0.501]

An unsaturated hydrocarbon X on ozonolysis gives A. Compound A when warmed with ammonical silver nitrate forms a bright silver mirror along the sides of the test tube. The unsaturated hydrocarbon X is:

10.0 mL of Na?CO? solution is titrated against 0.2 M HCl solution.
The following titre values were obtained in 5 readings:
4.8 mL, 4.9 mL 5.0 mL, 5.0 mL and 5.0 mL
Based on these readings, and convention of titrimetric estimation the concentration of Na?CO? solution is ________ mM. (Round off to the nearest integer).

The number of species below that have two lone pairs of electrons in their central atom is ________. (Round off to the nearest integer).
SF?, BF?, ClF?, AsF?, PCl?, BrF?, XeF?, SF?