Class 11th

(a) Classical mechanics applies to the macro world and hence fails when it is applied to the micro world. In the micro world, quantum mechanics incorporates all the principles like the uncertainty principle, dual behaviour etc.

(d) Rainbow is a continuous spectrum.

Assertion is a wrong statement but Reason is a correct one. Rainbow is a continuous spectrum.

This is a short answer type question as classified in NCERT Exemplar

(a) For n = 4, No. of sub-shells = (l = 0, l = 1, l = 2, l = 3) = 4.

(b) Total number of orbitals which can be present = n² = 4² = 16.
Each orbital can have an electron with m_s = – 1/2. Total no. of electrons with m, = – 1/2 is 16.

This is a short answer type question as classified in NCERT Exemplar

In presence of (Ph-CO-O)₂it lead to CH₃-CH₂-CH₂Br as the reaction undergo by free radical mechanism

However in absence of (Ph-CO-O)₂ the reaction undergo by carbocation intermediate thus lead to give CH₃-CHBr-CH₃

(a) P (Z=15) : [Ne]¹⁰3s²3p³  No. of unpaired electrons = 3
(b) Si (Z=14) : [Ne]¹⁰3s²3p²  No. of unpaired electrons = 2
(c) Cr (Z=24): [Ar]¹⁸4s¹3d⁵  No. of unpaired electrons = 6
(d) Fe (Z=26): [Ar]¹⁸4s²3d⁶  No. of unpaired electrons = 4
(e) Kr (Z=36) : [Ar]¹⁸4s²3d¹⁰4p⁶  No. of unpaired electrons = Nil.

Configuration of the two elements are:

Al (Z = 13): [Ne]¹⁰3s²3p¹

Si (Z = 14): [Ne]¹⁰3s²3p²
The unpaired electrons in silicon (Si) will experience more effective nuclear charge because the atomic number of the element Si is more than that of Al.

This is a short answer type question as classified in NCERT Exemplar

Greater the penetration of the electron present in a particular orbital towards the nucleus more will be the magnitude of the effective nuclear charge. Based upon this

(i) 2s orbital is closer to the nucleus than 3s orbital and hence it will experience more effective nuclear charge.

(ii) 4d orbital will experience more effective nuclear charge due to its closer proximity to 4f orbital.

(iii) 3p orbital will experience more effective nuclear charge as it is closer to the nucleus

This is a short answer type question as classified in NCERT Exemplar

The nitro group strongly deactivate the benzene towards the electrophilic substitution reaction due to the -R and -I effect