IIT-JEE-Chemistry-Final Revision Set No.59

1. If the Nitrogen atom had electronic configuration 1s7, it would have energy lower than that of the normal ground state configuration 1s2 2s2 2p3, because the electrons would be closer to the nucleus. Yet 1s7 is not observed because it violates
(A) Heisenberg uncertainty principle
(B) Hund's rule
(C) Pauli exclusion principle
(D) Bohr postulate of stationary orbits

2. Rutherford's experiment , which established the nuclear model of the atom, used a beam of
(A) β-particles , which impinged on a metal foil and got absorbed
(B) γ-rays, which impinged on a metal foil and got scattered
(C) Helium atoms , which impinged on a metal foil and got scattered
(D) Helium nuclei , which impinged on a metal foil and got scattered

3. When the temperature is increased, surface tension of water
(A) Increases
(B) Decreases
(C) Remains constant
(D) Shows irregular behaviour

4. A substance AX BY crystallizes in a face centered cubic (FCC) lattice in which atoms 'A' occupy each corner of the cube and atoms 'B' occupy the centers of each face of the cube. Identify the correct composition of the substance AX BY
(A) AB3
(B) A4B3
(C) A3B
(D) Composition cannot be specified

5. Consider the chemical reaction N2(g) + 3H2(g) --> 2NH3(g). The rate of this reaction can be expressed in terms of time derivative of concentration of N2(g), H2(g), or NH3(g). Identify the correct relationship amongst the rate expressions
(A) Rate = -d[N2]/dt = -1/3 d[H2] /dt = 1/2 d[NH3] /dt
(B) Rate = -d[N2]/dt = -3 d[H2] /dt = 2 d[NH3] /dt
(C) Rate = d[N2]/dt = 1/3 d[H2] /dt = 1/2 d[NH3] /dt
(D) Rate = -d[N2]/dt = - d[H2] /dt = d[NH3] /dt


Source: JEE 2002 screening