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) H2O
(C) SO2
(D) H2S
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) H2O
(B) H2O2
(C) D2O
(D) D2O2
Ans. (C) D2O
Q13. Which metal is used to prepare H2 with dil. H2SO4 ?
(A) Cu
(B) Hg
(C) Ag
(D) Zn
Ans. (D) Zn
Q14. What is formula of Baking Soda ?
(A) NaHCO3
(B) Na2CO3
(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 + H2
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.
Ans.
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 ?
Ans.
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).