Chapter 8: The d and f Block Elements
8.1. Silver atom has completely filled d orbitals (4d10) in its ground state. How can you say that it is a transition element?Ans: The outer electronic configuration of Ag (Z=47) is 4d105s1. It shows+1 and + 2 O.S….
Chapter 7: The p Block Elements
NCERT IN TEXT QUESTIONS 7.1. Why are pentahalides more covalent than trihalidcs?Ans: The group 15 elements have 5 e-1 s in their valence shell. It is difficult to lose 3e-1s to form E3+ and even more difficult to lose 5e-1 s to…
Chapter 6: General Principles and Processes of Isolation of Elements
6.1. Which of the ores mentioned can be concentrated by magnetic separation method?Ans: Ores Which are magnetic in nature can be separated from non-magnetic gangue particles by magnetic separation method. For ex: ores of iron such as haemetite…
Chapter 11: Work Power and Energy
NCERT Textbook for Class 9 Science – Page 148Q1: A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force. Let us take it that the force…
Chapter 5: Surface Chemistry
NCERT TEXTBOOK QUESTIONS SOLVED 5.1. Write any two characteristics of Chemisorption.Ans: Pt and Pd form inert electrodes, i.e., they are not attacked by the ions of the electrolyte or the products of electrolysis. Hence, they are used as…
Chapter 4: Chemical Kinetics
4.1.For the reaction R—>P, the concentration of reactant changes from 0.03 M to 0.02 M in 25 minutes. Calculate the average rate of reaction using units of time both in minutes and seconds.Ans. 4.2.In a reaction, 2A…
Chapter 9: Heredity and Evolution
Question 1.A Mendelian experiment consisted of breeding tall pea plants bearing violet flowers with short pea plants bearing whfte flowers. The progeny all bore violet flowers, but almost half of them are short. This suggests that the…
Chapter 3: Electrochemistry
3.1. How would you determine the standard electrode potential of the system Mg2+1 Mg?Ans: A cell will be set up consisting of Mg/MgSO4 (1 M) as one electrode and standard hydrogen electrode Pt, H, (1 atm)H+/(l M) as second electrode,…
Chapter 2: Solutions
2.1. Calculate the mass percentage of benzene (C6H6) and carbon tetrachloride (CCl4) if 22 g of benzene is dissolved in 122 g of carbon tetrachloride.Ans: Mass of solution = Mass of C6H6 + Mass of CCl4= 22 g+122 g=…
Class 12 Chemistry Chapter 1: The Solid State
1.1. Why are solids rigid?Ans: The constituent particles in solids have fixed positions and can oscillate about their mean positions. Hence, they are rigid. 1.2. Why do solids have definite volume?Ans: Solids keep their volume because of rigidity in…
