JEE Chemistry Some Basic Concepts Of Chemistry MCQs Set B

Question. The mass of 1 mole of electrons is
(a) 0.55 mg
(b) 9.1 × 10^–28g
(c) 1.008 mg
(d) 9.1 × 10^–27 g

Answer: A

Question. 10 g of hydrogen and 64 g of oxygen were filled in a steel vessel and exploded. Amount of water produced in this reaction will be:
(a) 4 mol
(b) 2 mol
(c) 3 mol
(d) 1 mol

Answer: A

Question. Which has the maximum number of molecules among the following ?
(a) 8 g H₂
(b) 44 g CO₂
(c) 48 g O₃
(d) 64 g SO₂

Answer: A

Question.  The simplest formula of a compound containing 50% of element X (atomic mass 10) and 50% of element Y (atomic mass 20) is
(a) X₂Y
(b) XY
(c) XY₃
(d) None of these

Answer: A

Question. Empirical formula of hydrocarbon containing 80% carbon and 20% hydrogen is
(a) CH₃
(b) CH
(c) CH₄
(d) CH₂

Answer: A

Question. The empirical formula of a compound is CH₂. One mole of this compound has a mass of 42 grams. Its molecular formula is
(a) C₃H₆
(b) CH₂
(c) C₃H₈
(d) C₂H₂

Answer: A

Question. In a hydrocarbon, mass ratio of hydrogen and carbon is 1:3, the empirical formula of hydrocarbon is
(a) CH₄
(b) C₂H
(c) CH₂
(d) CH₃

Answer: A

Question. An organic compound contains carbon, hydrogen and oxygen. Its elemental analysis gave C, 38.71% and H, 9.67%. The empirical formula of the compound would be
(a) CH₃O
(b) CHO
(c) CH₂O
(d) CH₄O

Answer: A

Question. A hydrocarbon is composed of 75% carbon. The empirical formula of the compound is
(a) CH₄
(b) CH₃
(c) CH₂
(d) C₂H₅

Answer: A

Question. 12 gm of Mg (atomic mass 24) will react completely with hydrochloric acid to give
(a) 1/2 mol of H₂
(b) One mol of H₂
(c) 2/3 mol of O₂
(d) both 1/2 mol of H₂ and 1/2 mol of O₂

Answer: A

Question. 20.0 kg of N_2(g) and 3.0 kg of H_2(g) are mixed to produce NH_3(g). The amount of NH_3(g) formed is
(a) 17 kg
(b) 20 kg
(c) 34 kg
(d) 3 kg

Answer: A

Question. 20.0 kg of H₂(g) and 32 kg of O₂(g) are reacted to produce H₂O(l). The amount of H₂O (l) formed after completion of reaction is
(a) 72 kg
(b) 62 kg
(c) 38 kg
(d) 42 kg

Answer: A

Question. What is the weight of oxygen required for the complete combustion of 2.8 kg of ethylene ?
(a) 9.6 kg
(b) 2.8 kg
(c) 6.4 kg
(d) 96 kg

Answer: A

Question. What is the molarity of 0.2N Na₂CO₃ solution?
(a) 0.1 M
(b) 0.4 M
(c) 0 M
(d) 0.2 M

Answer: A

Question. The molar solution of H₂SO₄ is equal to
(a) N/2 solution
(b) 2N solution
(c) N solution
(d) 3N solution

Answer: A

Question. Volume of water needed to mix with 10 mL 10N HNO₃ to get 0.1 N HNO₃ is :
(a) 990 mL
(b) 10 mL
(c) 1000 mL
(d) 1010 mL

Answer: A

Question. One kilogram of a sea water sample contains 6 mg of dissolved O₂. The concentration of O₂ in the sample in ppm is
(a) 6.0
(b) 16.0
(c) 0.6
(d) 60.0

Answer: A

Question. A 5 molar solution of H₂SO₄ is diluted from 1 litre to a volume of 10 litres, the normality of the solution will be
(a) 1N
(b) 5N
(c) 0.1N
(d) 0.5N

Answer: A

Question. With increase of temperature, which of these changes?
(a) Molarity
(b) Molality
(c) Weight fraction of solute
(d) Mole fraction

Answer: A

Question. 6.02 × 10²⁰ molecules of urea are present in 100 ml of its solution. The concentration of urea solution is
(a) 0.01 M
(b) 0.1 M
(c) 0.02 M
(d) 0.001 M

Answer: A

Question.  Two solutions of a substance (non electrolyte) are mixed in the following manner. 480 ml of 1.5 M first solution + 520 ml of 1.2 M second solution. What is the molarity of the final mixture?
(a) 1.344 M
(b) 1.20 M
(c) 2.70 M
(d) 1.50 M

Answer: A

Question. Which of the following statements are correct ?
(i) Both solids and liquids have definite volume.
(ii) Both liquids and gases do not have definite shape.
(iii) Both solids and gases take the shape of the container
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (i), (ii) and (iii)

Answer: A

Question. Choose correct option based on following statements. Here T stands for true statement and F for false statement.
(i) Homogeneous mixture has uniform composition throughout.
(ii) All components of a heterogeneous mixture are observable to naked eyes.
(iii) All solutions are homogeneous in nature.
(iv) Air is an example of heterogeneous mixture.
(a) TFTF
(b) TFFF
(c) TTFF
(d) FFTT

Answer: A

Question.  Read the following and choose the incorrect statements.
(i) Both weight and mass are same quantities used for measurement of amount of matter present in a substance
(ii) Mass and weight of a substance vary from one place to another due to change in gravity.
(iii) SI unit of mass is kilogram and while SI unit of weight is gram.
(a) All of these
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (i) and (ii)

Answer: A

Question. Moon takes 27.3 days to complete one orbit around the
Earth. Now read the following statements and choose the correct code. Here T is for true statement and F is for ‘False statement’.
(i) Moon takes 655.2 hours to complete one orbit around the Earth.
(ii) Moon takes 39312 seconds to complete one orbit around the earth.
(iii) Moon takes 1638 minutes to complete one orbit around the Earth
(a) T F F
(b) F T F
(c) T F T
(d) T T T

Answer: A

Question. Give the correct order of initials T or F for following statements. Use T if statement is true and F if it is false.
(i) Gay-Lussac’s law of gaseous volumes is actually the law of definite proportion by volume.
(ii) Law of conservation of mass is true for physical change, but not for chemical change.
(iii) The percentage of oxygen in H₂O₂ is different from that in H₂O. Hence, it violates law of definite proportions.
(iv) Fixed mass of A reacts with two different masses of B (say x and y), then the ratio of x/y can be any positive integer.
(v) At STP, 5 mL of N₂ and H₂ have different no. of molecules.
(a) TFFTF
(b) TTFTF
(c) FTTFT
(d) TFTTF

Answer: A

Question. Consider the following statements.
(i) Atoms of H, O, N and C have identical properties but different mass.
(ii) Matter is divisible into atoms which are further indivisible.
(iii) The ratio of N: H in NH₃ is 1 : 3 and N : O in nitric oxide is 2 : 1.
(iv) Dalton’s atomic theory support law of conservation of mass.
Which of the following pairs of statements is true according to Dalton’s atomic theory ?
(a) (ii) and (iv)
(b) (i) and (ii)
(c) (ii) and (iii)
(d) (i) and (iv)

Answer: A

Question. Choose the correct option based on following statements. Here ‘T’ stands for true and ‘F’ stands for false statement.
(i) Molecular mass of cane sugar (C₁₂H₂₂O₁₁) is 182 amu.
(ii) 1 mole of cane sugar contains 6.022 × 10²³ molecules of cane sugar.
(iii) 34.20 g of cane sugar contains 6.022 × 10²¹ molecules of cane sugar
(a) FTF
(b) TTF
(c) TFT
(d) FTT

Answer: A

Question. Assertion : Significant figures for 0.200 is 3 whereas for 200 it is 1.
Reason : Zero at the end or right of a number are significant provided they are not on the right side of the decimal point.
(a) Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : One atomic mass unit is defined as one twelfth of the mass of one carbon - 12 atom.
Reason : Carbon-12 isotope is the most abundunt isotope of carbon and has been chosen as standard.
(a) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. Assertion : Volume of a gas is inversely proportional to the number of moles of gas.
Reason : The ratio by volume of gaseous reactants and products is in agreement with their mole ratio
(a) Assertion is incorrect, reason is correct
(b) Assertion is correct, reason is incorrect
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : Equal moles of different substances containsame number of constituent particles.
Reason : Equal weights of different substances contain the same number of constituent particles
(a) Assertion is correct, reason is incorrect
(b) Assertion is incorrect, reason is correct
(c) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(d) Assertion is correct, reason is correct; reason is a correct explanation for assertion

Answer: A

Question. Assertion : The empirical mass of ethene is half of its molecular mass.
Reason : The empirical formula represents the simplest whole number ratio of various atoms present in a compound
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct

Answer: A

Question. If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will
(a) decrease twice
(b) increase two fold
(c) remain unchanged
(d) be a function of the molecular mass of the substance

Answer: A

Question. The maximum number of molecules are present in
(a) 15 L of H₂ gas at STP
(b) 0.5 g of H₂ gas
(c) 5 L of N₂ gas at STP
(d) 10 g of O₂ gas

Answer: A

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

Answer: A

Question. Volume occupied by one molecule of water
(a) 3.0 × 10^–23 cm³
(b) 9.0 × 10^–23 cm³
(c) 6.023 × 10^{– 23} cm³
(d) None of these

Answer: A

Question. The number of atoms in 0.1 mol of a triatomic gas is :
(N_A = 6.02 ×10²³ mol^–1)
(a) 1.806 × 10²³
(b) 1.800 × 10²²
(c) 6.026 × 10²²
(d) 3.600 × 10²³

Answer: A

Question. How much time (in hours) would it take to distribute one  Avogadro number of wheat grains if 10²⁰ grains are distributed each second ?
(a) 1.673
(b) 167.3
(c) 0.1673
(d) 16.73

Answer: A

Question. Arrange the following in the order of increasing mass (atomic mass: O = 16, Cu = 63, N = 14)
I. one atom of oxygen
II. one atom of nitrogen
III. 1 × 10^–10 mole of oxygen
IV. 1 × 10^–10 mole of copper
(a) II < I < III < IV
(b) III < II < IV < I
(c) I < II < III < IV
(d) IV < II < III < I

Answer: A

Question. If 1.5 moles of oxygen combines with Al to form Al₂O₃, the mass of Al in g [Atomic mass of Al = 27] used in the reaction is
(a) 54
(b) 81
(c) 2.7
(d) 40.5

Answer: A

Question. Which one of the following is the lightest?
(a) 0.1 g of silver
(b) 6.023 × 10²² molecules of nitrogen
(c) 0.1 mole of oxygen gas
(d) 0.2 mole of hydrogen gas

Answer: A

Question. In a compound C, H and N atoms are present in 9 : 1 : 3.5 by weight. Molecular weight of compound is 108. Molecular formula of compound is
(a) C₆H₈N₂
(b) C₂H₆N₂
(c) None of these
(d) C₃H₄N

Answer: A

Question. The empirical formula of an acid is CH₂O₂, the probable molecular formula of acid may be :
(a) CH₂O₂
(b) C₃H₆O₄
(c) CH₂O
(d) None of these

Answer: A

Question. A gaseous hydrocarbon gives upon combustion 0.72 g of water and 3.08 g. of CO₂. The empirical formula of the hydrocarbon is
(a) C₇H₈
(b) C₃H₄
(c) C₂H₄
(d) None of these

Answer: A

Question. Assuming fully decomposed, the volume of CO₂ released at STP on heating 9.85 g of BaCO₃ (Atomic mass, Ba = 137) will be
(a) 1.12 L
(b) 2.24 L
(c) 4.96 L
(d) 0.84 L

Answer: A

Question. The mass of BaCO₃ produced when excess CO₂ is bubbled through a solution of 0.205 mol Ba(OH)₂ is
(a) 40.5 g
(b) 162 g
(c) 81 g
(d) 20.25 g

Answer: A

Question. How many moles of lead (II) chloride will be formed from a reaction between 6.5 g of PbO and 3.2 g of HCl ?
(a) 0.029
(b) 0.333
(c) 0.044
(d) 0.011

Answer: A

Question. 10 mL of 2(M) NaOH solution is added to 200 mL of 0.5 (M) of NaOH solution. What is the final concentration ?
(a) 0.57 (M)
(b) 11.4 (M)
(c) 5.7 (M)
(d) 1.14 (M)

Answer: A

Question. If maximum fluoride ion presence was set to be 4 ppm number of moles of fluoride in 10 ml drinking water ?
(a) 2.10 × 10^–3
(b) 3.10 × 10^–3
(c) 2.10 × 10^–2
(d) 3.3 × 10^–2

Answer: A