CBSE Class 11 Chemistry Sample Paper Set 15

Q.1. Anything that influences the valence electrons will affect the chemistry of the element. Which of the following factors does not affect the valence shell?

   a) Valence principal quantum number b) Nuclear charge

   b) Nuclear mass d) Number of core electrons

Q.2. Considering the elements B, C, N, F, and Si, the correct order of their nonmetallic character is :

   a) B> C> Si> N> F b) Si> C> B> N> F

   c) F >N> C> B >Si d) F> N> C> Si> B

Q.3. What do you understand by the term limiting reagent? 

Q.4. How many electrons in an atom may have the following quantum numbers?

   a) n= 3 , ms = + ½ b) n = 4 , l = 0

Q.5. State the law of multiple proportions. 1M

Q.6. Indicate the number of unpaired electrons in S and Cr. 

Q.7. Express the following numbers in three significant figures: a)6.022 x 10²³ b) 34.21

Q.8. Find the energy of the photon which corresponds to the light of frequency 3 x 10¹⁵ Hz. 

Q.9. Explain why Be has higher ΔiH than B? 

Q.10. Calculate the mass of one molecule of sulphur dioxide (SO₂). 

Q.11. (1) What do you mean by threshold frequency?

(2) Why Bohr’s orbits are also known as energy levels? 

Q.12. How would explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium? 

Q.13. (1) What are the units of molarity? What is the effect of temperature on molarity of a solution?

(2) How are 0.50 mol Na₂CO₃ and 0.50 M Na₂CO₃ different? 

Q.14. (1) What are the possible values of n, l and m for the electron in 3p orbital?

(2) (a) What is the maximum number of electrons that can be accommodated in an orbital with ml = +3?

(b) Write the electronic configuration for copper. (at. no. 29). 

Q.15. Commercially available conc. HCI contains 38% HCl by mass. What is the molarity of this solution? The density is 1.10g m L^-1. 

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