HBSE Class 11 Chemistry Question Paper 2021 Answer Key

HBSE Class 11 Chemistry Question Paper 2021 Answer Key 

HBSE Class 11 Chemistry Previous Year Question Paper with Answer. HBSE Board Solved Question Paper Class 11 Chemistry 2021. HBSE 11th Question Paper Download 2021. HBSE Class 11 Chemistry Paper Solution 2021. Haryana Board Class 11th Chemistry Question Paper 2021 Pdf Download with Answer.



Q1. Number of moles in 64 g of Oxygen are : 

(A) 1.5  

(B) 2.0 

(C) 2.5  

(D) 3.0 

Ans. (B) 2.0 

32gm = 1 mole

No. of moles = 64/32 = 2 moles 


Q2. Find number of unpaired electrons in Nitrogen atom : 

(A) 1  

(B) 2 

(C) 3  

(D) 4 

Ans. (C) 3  


Q3. Arrange B, C, N, F  and Si in correct order of their non-metallic character. 

(A) B > C > Si  > N  > F  

(B) Si  > C > B > N  > F 

(C) F > N > C  > B  > Si 

(D) F > N > C  > Si  > B 

Ans. (C) F > N > C  > B  > Si 


Q4. How many horizontal rows in Modern periodic table ? 

(A) 2  

(B) 6 

(C) 7  

(D) 8 

Ans. (C) 7  


Q5. Which compound shows zero dipole moment ? 

(A) CCl4 

(B) H2

(C) SO

(D) H2

Ans. (A) CCl4


Q6. Which type of intermolecular force exists in 

(A) Dipole-dipole forces  

(B) Dipole-induced dipole forces 

(C) Dispersion forces  

(D) Hydrogen bond 

Ans. (A) Dipole-dipole forces 


Q7. A real gas acts as an ideal gas under which condition ? 

(A) High temperature, low pressure 

(B) Low temperature, high pressure 

(C) High temperature, high pressure 

(D) Low temperature, low pressure 

Ans. (A) High temperature, low pressure 


Q8. The enthalpies of all elements in their standard states are : 

(A) Unity 

(B) Zero 

(C) <0  

(D) >0 

Ans. (B) Zero 


Q9. The pH of milk is : 

(A) 7.4  

(B) 9.2 

(C) 7.8  

(D) 6.8  

Ans. (D) 6.8  


Q10. The oxidation number of Mn in KMnO4 is : 

(A) +1  

(B) +5 

(C) +7  

(D) +3 

Ans. (C) +7

1 + x + 4(-2) = 0 

1 + x – 8 = 0 

x = +7 


Q11. The oxidation number of Nitrogen in NO3– is : 

(A) −3  

(B) +1 

(C) +3  

(D) +5 

Ans. (D) +5 

x + 3(-2) = -1 

x – 6 = -1 

x = +5 


Q12. Which is heavy water ? 

(A) H2

(B) H2O2 

(C) D2

(D) D2O2 

Ans. (C) D2O


Q13. Which metal is used to prepare H2 with dil. H2SO

(A) Cu  

(B) Hg 

(C) Ag  

(D) Zn 

Ans. (D) Zn


Q14. What is formula of Baking Soda ? 

(A) NaHCO3

(B) Na2CO

(C) NaOH 

(D) KOH 

Ans. (A) NaHCO3


Q15. Which alkali metal gives hydrated salt ? 

(A) Li  

(B) Na 

(C) K  

(D) Cs 

Ans. (A) Li  


Q16. Thermodynamically the most stable form of Carbon is : 

(A) Coal  

(B) Graphites 

(C) Fullerenes 

(D) Diamond 

Ans. (B) Graphites 


Q17. CnH2n is general formula of : 

(A) Alkene 

(B) Alkane 

(C) Alkyne 

(D) Arene 

Ans. (A) Alkene 


Q18. Heating a mixture of sodium benzoate with soda-lime gives : 

(A) Methane 

(B) Benzene 

(C) Ethane 

(D) Propane 

Ans. (B) Benzene 


Q19. Round up 10.4107 upto three significant figures. 

Ans. 10.4 


Q20. Which of the following species will have smallest size ?  

Mg, Mg2+, Al, Al3

Ans. Al³+ 

Mg > Al > Mg²+ > Al³+


Q21. Write general electronic configuration of S-block elements.

Ans. ns¹-²


Q22. What is Charle’s Law ? 

Ans. Charles’s law states that if a given quantity of gas is held at a constant pressure, its volume is directly proportional to the absolute temperature. 

V ∝ T (Pressure = Constant)  


Q23. What is Constant in Boyle’s Law ? 

Ans. The pressure and volume of a gas are inversely proportional to each other as long as the temperature and the quantity of gas are kept constant. 

P ∝ 1/V (Temperature = Constant) 

P1/P2 = V2/V1 = constant 


Q24. What is reduction process ? 

Ans. Reduction is the transfer of electrons between species in a chemical reaction where there is a process of gaining electrons or a decrease in the oxidation state by an element.  

(Gain of Electron or Removal of Oxygen or Addition of Hydrogen)


Q25. Which is oxidizing agent in the following reaction ?    

Zn + 2HCl → ZnCl2 + H

Ans. HCl is oxidising agent. 


Q26. Why are alkali metals not found in nature ? 

Ans. Highly Reactive (so they make compound) 


Q27. 1 milligram = ………. kilogram

Ans. 1/1000000 or 10-⁶


Q28. Binary compound formed by Mg and N is ………. 

Ans. Mg3N2


Q29. Each line of V vs T graph at constant pressure is called ………. 

Ans. isobar


Q30. In a reaction donor of electrons called ………… 

Ans. Nucleophiles or electron donor or Lone pair or Base 


Q31. ………… number of coordinated bonded water molecules in CuSO4.5H2O. 

Ans. Four 


Q32. Group 15, 16, 17 hydrides called …………. 

Ans. e-rich hydrides or Covalent hydride or Non-Metal hydride


Q33. ………… is oxidation state of Na in Na2O. 


2x + (-2) = 0

2x = 2 

x = +1 

Oxidation state of Na in Na2O is +1. 


Q34. Group 2 Be, Mg, Ca, Sr, Ba are called …………… metals. 

Ans. Alkaline Earth 


Q35. The type of hybridization of carbon in graphite is ………….. 

Ans. sp²


Q36. Calculate the molarity of KOH in the solution prepared by dissolving its 5.6 g in water to form 250 mL of solution. 

Ans. Weight of KOH (W) = 5.6g 

Molecular weight of KOH (MW) = 56g 

Volume of solution (V) = 250mL 

Molarity (M) = W/MW × 1000/V = 5.6/56 × 1000/250 = 4/10 = 0.4 M 


Q37. Calculate frequency of radiation having wavelength 5800 Å. 

Ans.  v = c/λ = (3×10⁸) ÷ (5800×10-¹⁰) = 5.172 × 10¹⁴ s-¹


Q38. What is enthalpy of Combustion ? Give one example. 

Ans. Enthalpy of combustion of a substance is the change in enthalpy produced when one mole of the substance is completely burnt in air or oxygen at a given temperature. e.g. 

C(s) + ½O2(g) → CO(g) ∆H = -110.5 kJ mol-¹


Q39. What will be the conjugate bases for the Bronsted acids HF and H2SO4 ? 


Conjugate Acid → Bronsted Base 

HF                       → F- 

H2SO4                 → HSO4– 


Q40. What are Nucleophiles ? Give its types with examples. 

Ans. A nucleophile is a reactant which gives an electron pair to form a covalent bond. A nucleophile is usually charged negatively or is neutral with a lone couple of donatable electrons. e.g. H2O

Overall, the electron-rich species is a nucleophile.

Types– Negatively Charged Nucleophiles, All Lewis base which contains lone pairs, Ambident Nucleophile, Amphiphile Nucleophile


Q41. Explain Pauli Exclusion principle with example. 

Ans. The Pauli exclusion principle states that in a single atom no two electrons will have an identical set or the same quantum numbers (n, l, ml, and ms). To put it in simple terms, every electron should have or be in its own unique state (singlet state). 


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