Question Bank | Chem-11, Ch-01

Here is a vast collection of objective and subjective questions in this question bank of chemistry 11, chapter 01. Following types of questions have been included here.

  • MCQs (Textbook Exercise)
  • MCQs (Previous Boards Essentials)
  • SQs Topic-wise (Previous Boards Essentials + Textbook Conceptuals)
  • LQs (Previous Boards Essentials)

You can find solutions to these questions from our publication, “An Insight Into Objective Chemistry-11”.

MCQs (Textbook Exercise)

Q. Each question has four possible answers. Tick the correct one.

01: Isotopes differ in: (MLT-16)(DGK-16)(BWP-18,23)(RWP-21)(SWL-21)(LHR-23) 

(a) Properties which depend upon mass

(b) Arrangement of electrons in orbitals

(c) Chemical properties

(d) The extent to which they may be affected in electromagnetic field.

02: Which of the following statements is not true? (MLT-16)

(a) Isotopes with even atomic masses are comparatively abundant.

(b) Isotopes with odd atomic masses are comparatively abundant.

(c) Isotopes with even atomic masses and even atomic numbers are comparatively abundant.

(d) Isotopes with even atomic masses and odd atomic numbers are comparatively abundant.

03: Many elements have fractional atomic masses. This is because: (FSL-19,22)(LHR-21)(DGK-22)

(a) The mass of the atom is itself fractional.

(b) Atomic masses are average masses of isobars.

(c) Atomic masses are average masses of isotopes.

(d) Atomic masses are average masses of isotopes proportional to their relative abundance.

04: The mass of one mole of electron is: (MLT-17)(DGK-17,18,19,22)(RWP-17)(SWL-18,19)(BWP-18,19,22,22)(SRG-19,19)(GJR-19,19,22,23)(LHR-22,22)

(a) 1.008 mg                        

(b) 0.55 mg

(c) 0.184 mg                        

(d) 1.673 mg

05: 27 g of Al will react completely with how much mass of O2 to produce Al2O3? (MLT-16,17,19)(RWP-16,17,19)(SRG-17)(GJR-17,19)(LHR-18)(BWP-18,19)(DGK-18,23)(FSL-21,23)(SWL-21)

(a) 8 g of Oxygen                

(b) 16 g of Oxygen

(c) 32 g of Oxygen              

(d) 24 g of Oxygen

06: The number of moles of CO2 which contain 8.0 g of Oxygen: (DGK-16,17)(BWP-16,17,22)(AJK-16,19)(SRG-17)(LHR-17,18,23)(GJR-18)(FSL-18,19,22)(MLT-19)(RWP-19)

(a) 0.25             

(b) 0.50             

(c) 1.0 

(d) 1.50

07: The largest number of molecules are present in: (AJK-16)(FSL-16,17,19,23)(DGK-16,22)(RWP-17)(MLT-17,19)(LHR-17,19,19,23)(SRG-18,19) (GJR-22)(SWL-22)(BWP-22,23,23)

(a) 3.6 g of H2O                   

(b) 4.8 g of C2H5OH

(c) 2.8 g of CO                     

(d) 5.4 g of N2O5

08: One mole of SO2 contains: (LHR-16,18,19,22)(SRG-19)(MLT-19,23)(RWP-22)   

(a) 6.02×1023 atoms of Oxygen         

(b) 18.1×1023 molecules of SO2

(c) 6.02×1023 atoms of Sulphur

(d) 4 gram atoms of SO2

09: The volume occupied by 1.4 g of N2 at S.T.P is: (RWP-16)(LHR-16,17,19)(MLT-17)(SWL-17,19)(DGK-18,19)(SRG-18,23)(GJR-19)(AJK-19)(BWP-19,19)(FSL-22)

(a) 2.24 dm3        

(b) 22.4 dm3      

(c) 1.12 dm3      

(d) 112 cm3

10: A limiting reactant is the one which: (GJR-17,21,22)(DGK-21)RWP-22)

(a) Is taken in lesser quantity in grams as compared to other reactants.

(b) Is taken in lesser quantity in volume as compared to the other reactants.

(c) Gives the maximum amount of the product which is required.

(d) Gives the minimum amount of the product under consideration.

MCQs (Previous Boards Essentials)

Q. Each question has four possible answers. Tick the correct one.

01: The number of subatomic particles in atom is: (GJR-22)

(a) 3    

(b) 20  

(c) 50  

(d) 100

02: Which is a molecular ion? (FSL-23)


(b) Mg2+               

(c) Na+

(d) Ca2+

03: Which is not a molecular ion? (FSL-16)

(a) He+



(d) CO+

04: The phenomenon of isotopy was discovered by: (BWP-23,23)

(a) Millikan                                   

(b) J. Perrin

(c) Soddy                             

(d) Thomson

05: Nickel has isotopes: (DGK-17)(FSL-22)(GJR-23)

(a) 3    

(b) 5    

(c) 6    

(d) 11

06: Cadmium has isotopes: (SWL-17)(SWL-17)(MLT-17)

(a) 5    

(b) 6    

(c) 9    

(d) 2

07: The number of isotopes of oxygen is: (GJR-21) 

(a) Two             

(b) Three          

(c) Four             

(d) Five

08: Tin has isotopes: (RWP-21)(SWL-22)(DGK-23)

(a) 8    

(b) 9    

(c) 10  

(d) 11

09: The number of isotopes of calcium are: (DGK-22)

(a) 2    

(b) 3    

(c) 5    

(d) 6

10: Which of the following is a monoisotopic element? (SRG-23)

(a) Silver           

(b) Calcium       

(c) Chlorine      

(d) Fluorine

11: A pair of elements having single isotopes are: (MLT-21)

(a) 9F19, 79Au197                            

(b) 53I127, 35Br81

(c) 8O16, 7N14                       

(d) 33As75, 7N14

12: The pressure of vapours maintained in ionization chamber of mass spectrometer during isotopic analysis is: (DGK-19)

(a) 10–5 torr       

(b) 10–7 torr       

(c) 10–9 torr       

(d) 10-11 torr

13: The average atomic mass of Neon is: (BWP-21)

(a) 20.00           

(b) 20.18           

(c) 20.20           

(d) 22.0

14: Ascorbic acid is vitamin: (SRG-18)

(a) A   

(b) B   

(c) C   

(d) E

15: During combustion analysis, CO2 produced is absorbed in: (DGK-16)(FSL-19)

(a) Mg(ClO4)2                       

(b) 50% KOH

(c) CaCl2                              

(d) P2O5

16: The empirical formula of glucose is: (MLT-23)

(a) CHO           

(b) C2H4O2       

(c) CH2O          

(d) C6H12O6

17: A beaker contains 9 g of water. The number of H atoms in it is: (FSL-21)

(a) NA of atoms                    

(b) 2×NA of atoms

(c) 1/2NA of atoms               

(d) 3×NA of atoms

18: 1 mole of CH3OH and C2H5OH have: (MLT-21)

(a) Equal number of molecules

(b) Equal number of atoms

(c) Equal number of ions

(d) Equal number of protons

19: The number of moles of CO2 that contains 16 g of oxygen is: (DGK-23)(RWP-23)(SWL-23)

(a) 0.25

(b) 0.50           

(c) 1.0 

(d) 1.5

20: The number of moles of CO2 that contains 0.5 moles of oxygen is: (DGK-19)

(a) 0.25             

(b) 0.50             

(c) 1.0 

(d) 1.5

21: 22 g of CO2 sample has: (RWP-22)

(a) ½ mole of O atoms

(c) 1 mole of O atoms

(a) 1.5 mole of O atoms

(c) 6.02´1023 molecules of CO2

22: One gram formula of NaCl is equal to: (LHR-21)

(a) 58.5 g          

(b) 23 g            

(c) 35.5 g          

(d) 12 g

23: Mass in grams of 2.74 moles of KMnO4: (LHR-23)

(a) 0.715 g        

(b) 1416.2 g     

(c) 432.92 g      

(d) 294 g

24: The number of molecules in one dm3 of the water is: (GJR-22)(BWP-22)

(a) 6.02/22.4 ´1023              

(b) 18/22.4´1023

(c) 12.04/22.4 ´1023                

(d) 55.6´6.02´1023

25: The mass of 10 moles of electrons is: (RWP-23)

(a) 0.05 mg       

(b) 5.5 mg        

(c) 1.84 mg       

(d) 1.67 mg

26: The volume occupied by one mole of gas at STP is: (DGK-19)

(a) 54 dm3                           

(b) 22.414 dm3

(c) 2.24 dm3                        

(d) 2.4 dm3

27: The volume occupied by 1.6 g of O2 at S.T.P is: (RWP-22)

(a) 22.4 dm3     

(b) 2.24 dm3     

(c) 11.2 dm3     

(d) 1.12 dm3

28: One dm3 of N2 at STP contains about: (SWL-23)

(a) 5.37 ´ 1022 atoms           

(b) 3.01 ´ 1023 atoms

(c) 6.02 ´ 1023 atoms           

(d) 2.68 ´ 1019 atoms

29: The branch of chemistry which deals with calculations based on balanced chemical equation is called: (BWP-21)

(a) Thermochemistry           

(b) Thermometry

(c) Stoichiometry                 

(d) Physical chemistry

30: The branch of chemistry which tells us the quantitative relationship between reactants and products is called: (DGK-21)

(a) Thermochemistry           

(b) Thermometry

(c) Stoichiometry                 

(d) Physical chemistry

31: The mass of water formed when 2 grams of H2 and 64 g of O2 are combined together is: (FSL-23)

(a) 68 g             

(b) 36 g            

(c) 18 g             

(d) 66 g


1.1: ATOM

Q.01: What is the contribution of Greeks towards study of atom?

Q.02: What is the significance of John Dalton’s work about atom? (GJR-23)

Q.03: What is the contribution of J. Berzelius in chemistry?

Q.04: Why can atom not be seen with optical microscope?

Q.05: How can atom be seen with electron microscope?

Q.06: Differentiate between an ‘atom’ and a ‘molecule’. (MLT-16)

Q.07: Define the term atomicity. Give examples. (SRG-17,17)(MLT-18)(BWP-23)

Q.08: What are macromolecules? Give an example. (FSL-22)

Q.09: What are ions? Under what conditions are they produced? (SRG-17)(FSL-23)

Q.10: The formation of a positive ion is an endothermic reaction. Explain.

Q.11: The formation of a uninegative ion is an exothermic reaction. Explain.

Q.12: Define molecular ions with examples. (RWP-23)

Q.13: What is molecular ion? Give an example. (BWP-23)

Q.14: What are molecular ions? How are they generated? (AJK-16)(MLT-16,17,17)(BWP-18)(GJR-22)(RWP-22)(DGK-23)

Q.15: Differentiate between ion and molecular ion. (DGK-23)


Q.16: What is relative atomic mass? (MLT-18)

Q.17: Why we use the term relative atomic mass? (LHR-22)(DGK-22)

Q.18: What is amu? 


Q.19: Define isotopes and isotopy. (DGK-16)(AKJ-16,17)(FSL-22)

Q.20: What are isotopes? Give an example. (BWP-23)

Q.21: Why do isotopes have same chemical but different physical properties? (AJK-17)(LHR-23)(RWP-23)

Q.22: What are mono-isotopic elements?

Q.23: Define mass spectrometer and mass spectrometry.

Q.24: What is the principle of mass spectrometry? (DGK-22)

Q.25: Define mass spectrum.

Q.26: Draw a labelled diagram of Dempster’s mass spectrometer.

Q.27: What is the function of ionization chamber in mass spectrometer? (SRG-18)

Q.28: What is the function of magnetic field in mass spectrometer? (RWP-17,17)(LHR-17)(BWP-22)

Q.29: What is electrometer? Give its function in mass spectrometer. (SWL-23)

Q.30: Write down any four methods used for the separation of isotopes. (AJK-17)(RWP-18)(SRG-18)(DGK-23)

Q.31: Why do most of the elements have fractional atomic masses? (LHR-17)(SWL-17)(DGK22)

Q.32: No individual Neon atom in the sample of the element has a mass of 20.18 amu. Explain. (BWP-17)(SRG-17)(MLT-17,23)(GJR-17,23)(BWP-22)(DGK-23)(SWL-23)

Q.33: What is the justification of two equally strong peaks in the mass spectrum for bromine, while for iodine only one peak at 127amu is indicated? (GJR-16)(FSL-17,21,23)


Q.34: Differentiate between qualitative and quantitative analyses.

Q.35: Write down the formulas to determine the percentage of carbon and hydrogen in a compound. (RWP-22)

Q.36: Calculate the percentage of nitrogen in NH2CONH2. (RWP-17)(BWP-18)

Q.37: What are the steps to determine the empirical formula? 

Q.38: Why can the percentage of oxygen not be calculated directly in combustion analysis?             

Q.39: Differentiate between empirical formula and molecular formula. (MLT-16)(SWL-17)(DGK-17,23)(GJR-22)(BWP-22)

Q.40: Define Empirical Formula mass. (SWL-22)

Q.41: Define molecular formula. How is it related to empirical formula?

Q.42: How can you justify with example that molecular formula = n ´ empirical formula (AJK-16)(DGK-16,17)(MLT-17)(FSL-22)(RWP-22)(LHR-22)

Q.43: A compound may have same empirical and molecular formulas. Justify giving examples. (MLT-16)(LHR-17)


Q.44: Define mole with two examples. (LHR-21)(GJR-21)

Q.45: Define gram atom, giving examples. (SRG-18)(BWP-22)(FSL-23)

Q.46: Define gram molecule. (RWP-22)

Q.47: Define gram atom and gram molecule. (LHR-23)

Q.48: Define gram formula. Give two examples. (MLT-17)(DGK-21)(DGK-21)

Q.49: Define gram ion.                                                                                                    

Q.50: Differentiate between gram atom and gram ion. (GJR-23)

Q.51: Define molar mass.

Q.52: Mg atom is twice heavier as an atom of carbon. Explain. (GJR-17,22)(BWP-16,23)(LHR-17)(SWL-17,18)(AJK-17)(MLT-18)(DGK-21)(RWP-21)(FSL-22,22,23)(SRG-23)

Q.53: Justify that N2 and CO have same number of electrons, protons and neutrons. (SWL-21)(BWP-23)(FSL-16,17)(DGK-16,17,21)(LHR-16,16,21,22)(RWP-23)(SRG-23)

Q.54: One mg of K2CrO4 has thrice the number of ions than the number of formula units when ionized in water. Justify. (LHR-18)

Q.55: 23 g of Na and 238 g of Uranium have equal number of atoms in them. Justify it. (LHR-17)(RWP-17,21)(SWL-18)(DGK-21,22)

Q.56: 180 g of glucose and 342 g of sucrose have the same number of molecules but different number of atoms present in them. Give reason. (BWP-22)(MLT-23)(SWL-23)

Q.57: 58.5 amu is the formula mass of NaCl, but not the molecular mass. Why?

Q.58: Calculate the number of gram atoms (moles) in 0.1 g of sodium. (GJR-15)(RWP-15)(AJK-15)(MLT-16)(LHR-21)

Q.59: Calculate the number of gram atoms in 0.1 kg of silicon.

Q.60: How many molecules of water are there in 10 g of ice? (MLT-15)(DGK-22)(SWL-23)

Q.61: How many molecules of water are present in 3.6 grams of water? (FSL-23)  

Q:62: How many moles are present in 18 g of H2O? (GJR-23)

Q.63: Calculate the mass in grams of 10–3 moles of water. (GJR-14,15)

Q.64: Calculate the mass in grams of 2.74 moles of KMnO4. (GJR-17)(MLT-18)(FSL-21)(LHR-23)

Q.65: Calculate the mass in kilograms of 2.6 × 1020 molecules of SO2. (GJR-17)(MLT-18)(FSL-21)(DGK-23)

Q.66: Calculate the moles of chlorine atoms in 0.822 g of C2H4Cl2. (GJR-23)

Q.67: Calculate mass in grams of 5.136 moles of Ag2CO3. (GJR-17)(MLT-18)(FSL-21)

Q.68: Calculate the mass in grams of 2.78 ´ 1021 molecules of CrO2Cl2. (SWL-23)

Q.69: Define mole and Avogadro’s number. (RWP-22)

Q.70: Define Avogadro’s number. Give an equation to relate the Avogadro’s number and the mass of an element. (LHR-15,21)(DGK-16)(BWP-18)(MLT-21)

Q.71: When H2SO4 is dissolved in water, the number of ions is unequal, but the number of charges is equal. Explain.

Q.72: Define molar volume. (FSL-15)(DGK-14,17)(SWL-22)(GJR-23)

Q.73: One dm3 of different gases H2 and O2 have different masses but occupy same volume. Explain. (RWP-22)


Q.74: Define Stoichiometry. Give two assumptions for stoichiometric calculations. OR Define stoichiometry. Write down its two laws. (GJR-21)(LHR-21,23)(DGK-16,16)(MLT-16,17,17,21,21)

Q.75: What are the limitations of a chemical equation?

Q.76: Law of conservation of mass has to be obeyed during stoichiometric calculations. Explain. (LHR-14,21,22)(DGK-18,21,22)(RWP-18)(GJR-21)(SWL-21,22)

Q.77: One mole H2SO4 requires 2 moles of NaOH to neutralize it. Explain. (LHR-16)

Q.78: How many moles of CO2 can be produced from burning one mole of octane? Molar mass of octane is 114. (LHR-23)


Q.79: Define limiting reactant. Give an example. (FSL-14,21)(MLT-17,21)(SWL-18)

Q.80: Limiting reactant controls the amount of the product. Explain. (AJK-17,17)

Q.81: Why in some reactions, one of the reactants is used deliberately in excess quantity? (SWL-21)  

Q.82: What are the steps to identify a limiting reactant? (SRG-14)(FSL-14)(DGK-15)(MLT-16)(RWP-17)(BWP-18)(GJR-21)

Q.83: Many chemical reactions taking place in our surroundings involve limiting reactants. Explain. (FSL-17,18,22)(DGK-18)(LHR-22)(MLT-23)

1.8: YIELD

Q.84: Differentiate between actual yield and theoretical yield. (DGK-17,18)(BWP-17,23)(GJR-21)

Q.85: Why in most reactions, actual yield remains less than the theoretical yield? (FSL-16)(SRG-17,17,18)(RWP-17,21)(BWP-18,22)(MLT-18,21,21)(DGK-21)(LHR-22)

Q.86: Define percentage yield. Give an example. (LHR-23)

Q.87: What is the percentage yield?

Q.88: How can the efficiency of chemical reaction be calculated? Or What is the percentage yield? (FSL-18,21)(LHR-21)(RWP-22)(SRG-23)(SWL-23)



01: Explain isotopes with their relative abundance. (BWP-22)

02: Explain the construction and working of mass spectrometer. (RWP-22)


03: What is empirical formula? Discuss steps to calculate empirical formula. (BWP-23)

04: Write down various steps to calculate the empirical formula of a compound. (FSL-22)

05: Describe combustion analysis to determine the percentage of C, H and O in the organic compound. (LHR-22)(FSL-22)(DGK-22)(SRG-23)

06: Explain combustion analysis with diagram and write formulas for percentage of carbon, hydrogen and oxygen. (GJR-23)

07: A sample of liquid consisting of carbon, hydrogen and oxygen was subjected to combustion analysis. 0.5439 g of the compound gave 1.039 g of CO2, 0.6369 g of H2O. Determine the empirical formula of the compound. (MLT-17)(DGK-16,16,18)

08: The combustion analysis of an organic compound shows it to contain 65.44% carbon, 5.50% hydrogen and 29.06% or oxygen. What is the empirical formula of the compound? If the molecular mass of this compound is 110.15 g mol-1. Calculate the molecular formula of the compound. (RWP-16)(LHR-16)

09: Ethylene glycol is used as automobile antifreeze. It has 38.7% carbon, 9.7% hydrogen and 51.6% oxygen. Its molar mass is 62.1 g mole-1. Determine its empirical formula. (LHR-17)


10: A well-known ideal gas is enclosed in a container having volume 500 cm3 at S.T.P. Its mass comes out to be 0.72 g. What is the molar mass of this gas? (AJK-16,17)(MLT-16,16,17)(DGK-17)(BWP-18)(SWL-18)

11: Define the following terms with two, two examples of each: 1) Gram Formula 2) Gram Ion 3) Gram Atom 4) Percentage Yield (DGK-22)

12: Define the following terms with examples: (i) Relative atomic mass (ii) Molecular ion (iii) Isotope (iv) Molar volume (LHR-23)

13: Calculate the gram atoms (moles) in: (i) 0.1 g of sodium (ii) 0.1 kg of silicon. (DGK-21)

14: 10 grams of H3PO4 have been dissolved in excess of water to dissolve completely into ions. Calculate: (i) Masses of individual ions. (ii) Number of positive and negative charges dispersed in solution. (MLT-21)


15: Define stoichiometry. Write down its assumptions. (SWL-23)

16: Define stoichiometry. Give its assumptions. Mention two laws which help to perform the stoichiometric calculations. (BWP-23)(MLT-23)(RWP-23)

17: Mg metal reacts with HCl to give hydrogen gas. What is the minimum volume of HCl solution (27% by weight) required to produce 12.1 g of H2? The density of HCl solution is 1.14 g/cm3. (DGK-17,21)(MLT-21)

18: Calculate the number of grams of K2SO4 and water produced when 14 g of KOH are reacted with excess of H2SO4. Also calculate the number of molecules of water produced? (LHR-17,21)(DGK-21)(FSL-21)(FSL-21)

19: Serotonin (Molar mass = 176 g mol–1) is a compound that conducts nerve impulses in brain and muscles. It contains 68.2% C, 6.86% H, 15.09% N, and 9.08% O. What is its molecular formula? (BWP-17)


20: Write a note on limiting reactant and explain it with help of two examples. (SWL-22)(RWP-22)(FSL-23)

21: What is limiting reactant? How does it control the quantity of product in a chemical reaction? Give two examples. (BWP-22)

22: What is limiting reactant? Give two examples. How limiting reactant can be identified? (GJR-23)

23: Define limiting reactant. And give the suitable examples, and also write down the steps to find limiting reactant. (GJR-22)(SWL-23)

24: NH3 gas can be prepared by heating together two solids NH4Cl and Ca(OH)2. If a mixture containing 100 grams of each solid is heated, then how many grams of NH3 is produced? 2NH4Cl(s) + Ca(OH)2 (s) → CaCl2(s) +2NH3(g) + 2H2O(ℓ) (LHR-16,21)(MLT-16)(BWP-17)(RWP-21)

1.8: YIELD

25: Define yield. Differentiate between actual and theoretical yield. How percentage yield can be calculated? (DGK-23)

26: What is the difference between actual yield and theoretical yield? Why actual yield is less than theoretical yield? (RWP-22)(GJR-22)

27: Define types of yield. How do we calculate the percentage yield of a reaction? (LHR-23)

28: When lime stone (CaCO3) is roasted, quick lime (CaO) is produced according to the following equation. The actual yield of CaO is 2.5 kg, when 4.5 kg of lime stone is roasted. What is the percentage yield of this reaction? CaCO3 (s) → CaO(s) + CO2(g) (FSL-16,17,21)(SRG-17)(RWP-17,17)(GJR-21)

29: Silicon carbide (SiC) is an important ceramic material. It is produced by allowing sand (SiO2) to react with carbon at high temperature.  SiO2 + 3C → SiC + 2CO When 100 kg sand is reacted with excess of carbon, 51.4 kg of SiC is produced. What is the percentage yield of SiC? (DGK-18)

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