Please refer to Chapter 1 Some Basic Concepts of Chemistry MCQ Class 11 Chemistry with answers below. These multiple-choice questions have been prepared based on the latest NCERT book for Class 11 Chemistry. Students should refer to MCQ Questions for Class 11 Chemistry with Answers to score more marks in Grade 11 Chemistry exams. Students should read the chapter Some Basic Concepts of Chemistry and then attempt the following objective questions.

MCQ Questions Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry

The Some Basic Concepts of Chemistry MCQ Class 11 Chemistry provided below covers all important topics given in this chapter. These MCQs will help you to properly prepare for exams.

Question. The total number of electrons in 18 mL of water ( density = 1 g mL^-1 ) is 
(a) 6.02 x 10²⁵
(b) 6.02 x 10²⁴
(c) 6.02 x 18 x 10²³
(d) 6.02 x 10²³       

Question. Which of the following has the smallest number of molecules ? 
(a) 0.1 mole of CO₂ gas
(b) 11.2 L of CO₂ gas at STP
(c) 22 g of CO₂ gas
(d) 22.4 x 10³ mL of CO₂ gas at STP     

Question. An aromatic hydrocarbon with empirical formula, C₅H₄ on treatment with concentrated H₂SO₄ gave a monosulphonic acid. 0.104 g of the acid required 10 mL of N/20 NaOH for complete neutralisation. The molecular fo1mula of hydrocarbon is 
(a) C₅H₄
(b) C₁₀H₈
(c) C₁₅H₁₂
(d) C₂₀H₁₆
(e) C₁₅H₂₀     

Question. 10 g of sample of mixture o fCaC1₂ and NaCl is treated to precipitate all the calcium as CaCO₃ . This CaCO₃ is heated to convert all the Ca to CaO and the final mass of CaO is 1.62 g. The per cent by mass of CaCI₂ in the original mixture is 
(a) 32.1%
(b) 16.2%
(c) 21.8%
(d) 12.0%       

Question. 2.76 g of silver carbonate on being strongly heated yields a residue weighing 
(a) 3.54g
(b) 3.0g
(c) l.36g
(d) 2.16g         

Question. 4.6 x 10²² atoms of an element weigh 13.8 g. The atomic weight of that element is 
(a) 290
(b) 180
(c) 34.4
(d) 10.4   

Question. Arrange the following in the order of increasing mass. (Atomic mass of O = 16, Cu= 63, N = 14)
I. One atom of oxygen.
II One atom of nitrogen.
III. 1x 10^-10 to mole of oxygen.
IV. 1 x 10^-10 mole of copper
(a) II < I < III < IV
(b) I < II < III < IV 
( c) III < II < IV < I
( d) IV < II < III < I            

Question. A student performs a titration with different burettes and finds titre values of25.2 mL, 25.25 mL, and 25.0 mL. The number of significant figures in the average titre value is
(a) 1
(b) 2
(c) 3
(d) 4   

Question. Number of atoms of He in 100 u of He (atomic weight of He is 4) are
(a) 25
(b) 100
(c) 50
(d) l00 x 6x 10^-23   

Question. The mass of potassium dichromate crystals required to oxidise 750 cm³ of0.6 M Mohr’s salt solution is (Given, molar mass : potassium dichrornate = 294, Mohr’s salt= 392)
(a) 0.49 g
(b) 0.45 g
(c) 22.05 g
(d) 2.2 g     

Question. Stoichiometric ratio of sodium dihydrogen orthophosphate and sodium hydrogen orthophosphate required for synthesis of Na₅P₃O₁₀ is
(a) 1.5 : 3
(b) 3 : 1.5
(c) 1 : 1
(d) 2 : 3     

Question. 2 g of O₂ at 0°C and 760 mm of Hg pressure has volume
(a) 1.4 L
(b) 2.8 L 
(c) 11.2 L 
(d) 22.4 L     

Question. 2 g of metal carbonate is neutralised completely by 100 mL of0.1 N HCL The equivalent weight of metal carbonate is
(a) 50
(b) 100 
(c) 150
(d) 200       

Question. A compound contains 69.5% oxygen and 30.5% nitrogen and its molecular weight is 92. The formula of the compound is
(a) N₂O
(b) NO₂
(c) N₂O₄
(d) N₂O₅        

Question. An organic compound has an empirical formula (CH₂O), its vapour density is 45. The molecular formula of the compound is 
(a) CH₂O
(b) C₂H₅O
(c) C₂H₂O
(d) C₃H₆O₃       

Question. If the molecular weight of Na₂S₂O₃ and 1₂ are M₁ and M₂ respectively, then what will be the equivalent weight of Na₂S₂O₃ and 1₂ in the following reaction?
2S₂O₃^2- + 1₂ → S⁴O₆²– +2Ι^–
(a) M₁ , M₂
(b) M₁ , M₂/2
(c) 2M₁, M₂
(d) M₁, 2M₂       

Question. Number of atoms in 560 g ofFe (atomic mass 56 g mo1^-1) is 
(a) twice that of70 g N
(b) half that of 20 g H
(c) Both are correct
(d) None of the above       

Question. The equivalent mass of Fe in FeO is 
(a) 56
(b) 28
(c) 36
(d) 18.66       

Question. Amount of oxalic acid present in a solution can be determined by its titration with KMnO4 solution in the presence of H₂SO₄ . The titration gives unsatisfactory result when carried out in the presence ofHCl because HCI
(a) gets oxidised by oxalic acid to chlorine
(b) furnishes H⁺ ions in addition to those from oxalic acid
(c) reduces permanganate to Mn²⁺
(d) oxidises oxalic acid to carbon dioxide and water     

Question. The number of gram molecules of chlorine in 6. 02 x 10²⁵ hydrogen chloride molecules is
(a) 10
(b) 100
(c) 50
(d) 5     

Question. Excess of carbon dioxide is passed through 50 mL of0.5 M calcium hydroxide solution. After the completion of the reaction, the solution was evaporated to dryness. The solid calcium carbonate was completely neutralised with 0.1 N hydrochloric acid. The volume of hydrochloric acid required is ( atomic mass of calcium = 40) 
(a) 300 cm³
(b) 200 cm³
(c) 500 cm³
(d) 400 cm³         

Question. MnO^–₄ ions are reduced in acidic condition to Mn²⁺ ions whereas, they are reduced in neutral condition to MnO₂ . The oxidation of 25 mL of a solution X containing Fe²⁺ ions required in acidic condition 20 mL of a solution Y containing MnO₄ ions. What volume of solution Y would be re9iuired to oxidise 25 mL of a solution X containing Fe²⁺ ions in neutral condition?
(a) 11.4 mL
(b) 12.0 mL
(c) 33.3 mL
(d) 35.0 mL
(e) 25.0 mL         

Question. Sodium nitrate on reduction with Zn in presence of NaOH solution produces NH₃ . Mass of sodium nitrate absorbing 1 mole of electron will be 
(a) 7.750
(b) 10.625
(c) 8.000
(d) 9.875         

Question. The co1Tectly repo1ted answer of the adilition of 4.523, 2.3 and 6.24 will have significant figures
(a) two
(b) three
(c) four
(d) five   

Question. 1 L oxygen gas at STP will weigh
(a) 1.43 g
(b) 2.24 g
(c) 11.2 g
(d) 22.4 g           

Question. How many moles of magnesium phosphate, Mg₃ (PO₄)₂  will contain 0.25 mole of oxygen atoms ? 
(a) 0.02
(b) 3.125 X 10^-2
(c) 1.25 X 10^-2
(d) 2.5 X 10^-2     

Question. The stoichiometry of the following reaction is
    K₂S₂O₈ (aq)+ 2KI(aq) → 2K₂SO₄ (aq)+ I₂(aq)
(a) 2: 2
(b) I : 1
(c) I : 2
(d) 2 : l       

Question. Consider a titration of potassium dichromate solution with acidified Mohr’s salt solution using diphenylarnine as indicator. The number of moles of Mohr’s salt required per mole of dichromate is 
(a) 3
(b) 4
(c) 5
(d) 6           

Question. A compound has the molecular formula, X₄O₆ . If 10 g of X₄O₆  has 5.72 g X, then calculate atomic mass of X.
(a) 32u
(b) 64u 
(c) 67u
(d) 98u     

Question. The decomposition of a certain mass of CaCO₃ gave I l.2dm³ of CO₂ gas at STP. The mass of KOH required to completely neutralise the gas is 
(a) 56g
(b) 28g
(c) 42g
(d) 20g         

Question. The equivalent mass of a certain bivalent metal is 20. The molecular mass of its anhydrous chloride is
(a) 111
(b) 55.5
(c) 75.5
(d) 91       

Question. The equivalent weight of K₂Cr₂O₇ in acidic medium is expressed in terms of its molecular weight (M) as
(a) M/3
(b) M/4 
(c) M/6 
(d) M/7     

Question. An alkaloid contains 17.28% of nitrogen and it’s molecular mass is I 62. The number of nitrogen atoms present in one molecule of alkaloid is 
(a) 5
(b) 4
(c) 3
(d) 2       

Question. A gas is found to have a fom1ula [CO]_x. Its vapour density is 70, the x is 
(a) 3.0
(b) 3.5
(c) 5.0
(d) 6.5     

Question. The formula mass of Mohr’s salt is 392. The iron present in it, is oxidised by KMnO4 in acidic medium. The equivalent mass of Mohr’s salt is 
(a) 392
(c) 278
(b)31.6
(d) 156   

Question. A bivalent metal has an equivalent mass of 32. The molecular mass of the metal nitrate is 
(a) 182
(b) 168
(c) 192
(d) 188     

Question. 74.5 g ofametallic chloride contains 35.5 g ofchlorine, the equivalent weight of the metal is
(a) 19.5
(b) 35.5
(c) 39
(d) 78.0     

Question. 3 g of an ox.ide of a metal is converted to chloride completely and it yielded 5 g of chloride. The equivalent weight of the metal is
(a) 33.25
(b) 3.325
(c) 12
(d) 20       

Question. 4 g of copper was dissolved in concentrated nitric acid. The copper nitrate solution on strong heating gave 5 g of its oxide. The equivalent weight of copper is 
(a) 23
(b) 32
(c) 12
(d) 20       

Question. The enthalpy of combustion of methane at 25°C is 890 kl The heat liberated when 3.2 g of methane is bwnt in air is
(a) 445 kJ
(b) 278 kJ 
(c) – 890kJ
(d) l 78 kJ           

Question. What is the weight of oxygen that is required for the complete combustion of2.8 kg of ethylene?
(a) 9.6 kg
(b) 96.0 kg
(c) 6.4 kg
(d) 2.8 kg     

Question. Of two ox.ides of iron, the first contained 22% and the second contained 30% of oxygen by weight. The ratio of weights of iron in the two ox.ides that combine with the same weight of oxygen, is
(a) 3 : 2
(b) 2 : 1
(c) 1 : 2
(d) 1 : 1     

Question. When 10 g of 90% pure limestone is heated completely, the volume (in litres) of CO₂ is liberated at STP is 
(a) 22.4
(b) 2.24
(c) 20.16
(d) 2.016       

Question. The volume of oxygen necessary combustion of 20 L of propane is for the complete
(a) 40L
(b) 60 L
(c) 80 L
(d) 100 L         

Question. The mass of 112 cm³ of CH₄ gas at STP is
(a)0.16g
(b)0.8g
(c)0.08g
(d) 1.6 g     

Question. The total number of protons in 10 g of calcium carbonate is (No = 6. 023 X 10²³ ) 
(a) 3.01 X 10²⁴
(c) 2.0l x 10²⁴
(b) 4.06x 10²⁴
(d) 3.02x 10²⁴           

Question. Which of the following contains greatest number of oxygen atoms? 
(a) 1 g of O
(b) 1 g of O₂
(c) 1 gof O₃
( d) All have the same number of atoms   

Question. Camphor is often used in molecular mass determination because 
(a) it is readily available
(b) it has a very high cryoscopic constant
(c) it is volatile
(d) it is solvent for organic substances       

Question. What is the equivalent weight of SnC1₂ in the following reaction,
               SnC1₂ + Cl₂ → SnC1₄
(a) 95
(c) 60
(b) 45
(d) 30     

Question. If molecular weight of KMnO4 is M, then its equivalent weight in acidic medium would be 
(a) M
(b) M/2
(c) M/5
(d) M/3       

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