Chemistry Basic Concepts MCQs Chapter 1 Class 11

Chemistry Basic Concepts MCQs – Chapter 1 Class 11

Chemistry Basic Concepts is the foundation chapter of Class 11 Chemistry and is extremely important for FSc Part-I exams and entry test preparation. Questions from this chapter are frequently asked in MDCAT, NUMS, AKU, NUST, UET ECAT, and board examinations. It covers essential topics such as units and measurements, mole concept, stoichiometry, significant figures, empirical and molecular formulas, and limiting reagents, which are required throughout Chemistry.

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Created on February 10, 2022 By Ali Durrani

Chemistry Ch 1 Class 11 Introduction to Fundamental Concepts of Chemistry

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1 / 72

Actual yield is always experimental yield.

Less than

More than

Same as

None of the above

2 / 72

Which of the following will react with water?

NUMS 2016
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) CHCl3

B) Cl3CCHO

C) CHI4

D) ClCH2CH2Cl

3 / 72

Which of the following has six isotopes?

PMC Practice 27
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Cadmium

B) Tin

C) Palladium

D) Carbon

4 / 72

Mass spectrometer is used to determine which of the following quantity?

) Atomic mases

Atomic number

Both a and b

None of these

5 / 72

Isotopes are the atoms of same element having different number of _____.

PMC Practice 26
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Electrons

B) Protons

C) Positrons

D) Neutrons

6 / 72

The efficiency of a chemical reactions can be checked by calculating ________ yield.

PMC Practice 30
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Percentage

B) Actual

C) Theoretical

D) All of these options are correct

7 / 72

Glucose(C6H12O6) is the most important nutrient in a cell for generating chemical potential energy, what is the mass percent of carbon in 1.5g of sample?

PMC Practice 24
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 33%

B) 40%

C) 53.3%

D) 6.67%

8 / 72

The break down of molecular ions from natural productsgive important information about?

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Size

B) Position

D) Structure

C) Shape

9 / 72

How many molecules are there in 2.1 moles of CO₂:

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 3.49 x 10⁻²⁴

B) 2.53 x 10²⁴

C) 1.26 x 10²⁴

D) 3.79 x 10²⁴

10 / 72

Chemical equations do not tell about the ______ because of certain limitations.

PMC Practice 29
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) rate of reaction

B) pressure

C) conditions

D) Both A & C

11 / 72

Different kinds of atoms of the same element are called isotope having different __________but same ___________ properties.

PMC Practice 1
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Physical, atomic

B) Physical, chemical

C) Chemical, physical

D) Chemical, atomic

12 / 72

One mole of substance at STP has:

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Stoichiometry
States of Matter – Gases, Liquids and Solids
Elimination Tool:

A) 2.24 dm³

B) 24.4 dm³

C) 2.44 dm³

D) 22.4 dm³

13 / 72

The _____ study of composition of pure substance in 17th century clearly shows that few elements are components of many substances

PMC Practice 29
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) qualitative

B) quantitative

C) both A & B

D) extensive

14 / 72

Which of the following represents Empirical Formula of Glucose?

CH2O

CHO

C2H0

CHO2

15 / 72

Spectrometry is used when reactants and products absorb _____.

PMC Practice 7
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Ultraviolet radiations

B) Visible radiation

C) Infrared radiation

D) All of these

16 / 72

What is the mass of 10^-3 moles of MgSO4?

120 gram

12 grams

1.2 grams

0.12 gram

17 / 72

How many significant figures are there in 0.4793?

NTS 2018
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 3

B) 4

C) 5

D) 6

18 / 72

In combustion analysis method CO2 is absorbed by?

Mg(OH)2

KOH

Mg(CIO)2

None of thes

19 / 72

27 g of Al will react with how much mass of O2 to produce Al2O3?

PMC Practice 22
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 8g of oxygen

B) 16g of oxygen

C) 32g of oxygen

D) 24g of oxygen

20 / 72

Natural gas in homes burns in excess of oxygen, what is the limiting reactant in this case?

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Oxygen

B) Natural gas

C) Air

D) There is no limiting reactant

21 / 72

Which of the following has six isotopes?

PMC Practice 4
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Manganese

B) Tin

C) Calcium

D) Carbon

22 / 72

The atoms of hemoglobin is heavier than H-atoms

PMC Practice 23
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 67,000 times

B) 68,000 times

C) 65,000 times

D) 69,000 times

23 / 72

Mass spectrometer can be used to find:

Mass of atom

Mass of ion

Charge to mass ratio of atom

Charge to mass ratio of ion

24 / 72

Molecular formula = n (Empirical formula). What does “n” represents in this

Molecular number

Integer

Odd number

Sum of 2 number

25 / 72

_______ is a macromolecule found in blood.

PMC Practice 23
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Hemoglobin

B) Plasma

C) Creatinine

D) Plasmids

26 / 72

Which of the following molecule is expressed in empirical formula:

C6H12O6

C6H6

Na2S4O6

C2 H5

27 / 72

How many moles of S02 contain 16 grams of oxygen?

0.5

2.4

28 / 72

What will be the mass in grams of 12 gram atom of carbon atoms?

12.66 x 10^-24

1.66 x 10^-24

1.992 x 10^-23

2.660 x 10^-23

29 / 72

The smallest number of molecules are present in?

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 3.6g of H2

B) 4.8g of C2H5OH

C) 2.8 g of CO

D) 5.4 g of N2O5

30 / 72

A compound has an empirical (simple) formula, C2H2O. If the experimental molecular weight is found to be in the range 160-170, the molecular formula of this compound is:

(Atomic weight: C = 12.1, H = 1.008, O = 16).

PMC Practice 21
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) C3H6O3

B) C4H4O2

C) C8H8O4

D) C6H6O3

31 / 72

If you need to produce carbon dioxide from 12 grams of carbon, how many grams would you need?

32 / 72

The atomic mass, molecular mass, ionic mass or formula mass of a substance expressed in grams is called:

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Mole of a substance

B) Weight of substance

C) Mass of substance

D) Molar mass of substance

33 / 72

Mass of a neutron in amu is?

1.008386

1.007376

0.0005

None

34 / 72

If 9.8 g of sulfuric acid is dissolved in excess quantity of water, it will yield ____ moles of hydrogen ion (H+) and _____ moles of sulphate ions (SO42-).

PMC Practice 7
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 0.1, 0.2

B) 0.1, 0.3

C) 0.2, 0.4

D) 0.2, 0.1

35 / 72

2 moles of octane ( C8H18) burn with 25 moles of oxygen (02) and produced __ moles of carbon dioxide along with 18 moles of water.

PMC Practice 20
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 14

B) 16

C) 18

D) 2

36 / 72

Which of the following statement about Avogadro’s hypothesis is correct?

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Under similar conditions of temperature and pressure, gases react with each other in simple ratio.

B) Under similar conditions of temperature and pressure, equal volumes of all gases contain same number of molecules.

C) At NTP all gases contain same number of molecules.

D) Gases always react with gases only at given temperature and pressure.

37 / 72

The total number of neutrons in 5g of H2O are:

1 NA = 6.023 x 1023

PMC Practice 18
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 25 NA

B) 1.1 NA

C) 2.5 NA

D) 0.5 NA

38 / 72

X-ray work in 20th century shows that diameter of the atoms are of the order?

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 1nm.

B) 2nm.

C) 3nm.

D) 4nm.

39 / 72

A mole of a substance contains _____ particles.

PMC Practice 7
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 6.2×1022

B) 6.22×1022

C) 6.02×1023

D) 6.5×1022

40 / 72

In the ion-electron method of balancing equations, how oxygen is balanced?

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) O is balanced by adding H₂O

B) O is balanced by adding OH

C) All of these

D) O is balanced by adding O₂

41 / 72

In which of the following will water evaporate earlier?

PMC Practice 1
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Cup

B) Saucepan

C) Glass

D) Small bowl

42 / 72

Find the mass in grams of 1.69 mol of phosphoric acid.

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 165.6 g

B) 157 g

C) 148 g

D) 138 g

43 / 72

If the number of molecules of different gases are the same at S.T.P., the occupied volume will be _____.

PMC Practice 24
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Greater

B) Same

C) Smaller

D) Twice

44 / 72

1 amu is?

1.66 x 10^-27 kg

1.602 x 10^27 kg

1.66 x 10^-31 kg

None

45 / 72

The unit used to express the relative atomic mass is called?

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Gram unit.

B) Avigadro's number.

C) Atomic mass.

D) Atomic mass unit.

46 / 72

The mass number of an atom is:

PMC 2021 Tested
Chemistry
Fundamental Principles of Organic Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) The number of electrons

B) The number of neutrons

C) The number of protons

D) The number of neutrons and protons

47 / 72

If we are given the mass of a substance ,we can calculate the_______ of the other substance with the help of a balanced chemical equation.

Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Mass

B) Volume

C) Moles

D) All of these

48 / 72

Limiting reactant controls the amount of _.

PMC Practice 27
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Reactant

B) Products

C) Both A&B

D) None of these

49 / 72

Physical and chemical properties of an element depend upon

Atomic mass only

Atomic number only c

Atomic mass and atomic number respectively

Atomic number and atomic mass respectively

50 / 72

Solution contains 85.5 g of sucrose (C12H22O11) in 250 cm3. What is its molarity?

UHS 2019
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 1 M

B) 0.5 M

C) 0.25 M

D) 2 M

51 / 72

Chemical properties of an atom depends upon number of

Electron

Neutrons

Protons

Nucleons

52 / 72

It is the fact that 22.414 cm3 of any gas has a different masses but the same number of

PMC Practice 27
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Atoms

B) Particles

C) Molecules

D) None of these

53 / 72

One mole of Oxygen has number of atoms as compared to one mole of Nitrogen

equal

Half

Double

Quarter

54 / 72

Actual yield is always less than theoretical yield due to

PMC Practice 27
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Operational losses

B) Reaction reversibility

C) Side reaction

D) All of these

55 / 72

If 9.8 g of sulfuric acid is dissolved in excess quantity of water, it will yield ____ moles of hydrogen ion (H+) and ____ mole of sulphate ions (SO4-2).

PMC Practice 26
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 0.1, 0.2

B) 0.1, 0.3

C) 0.2, 0.4

D) 0.2, 0.1

56 / 72

The unit used to express the relative atomic mass is called

PMC Practice 4
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Gram unit

B) Avogadro's number

C) Atomic mass

D) Atomic mass unit

57 / 72

0.5 mole of SO2 contains gram of oxygen?

None

58 / 72

In mass spectrometry, ionization occurs in form.

Solid

Liquid

Vapor

No ionization occurs during the process.

59 / 72

Mass of an atom ranges from?

PMC Practice 20
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 1 x 10-28 kg to 1 x 10-22 kg

B) 1 x 10-26 kg to 1 x 10-23 kg

C) 1 x 10-27 kg to 1 x 10-24 kg

D) 1.6373 x 10-27 kg to 1 x 10-25 kg

60 / 72

Actual yield is always less than theoretical yield due to

PMC Practice 29
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) operational losses

B) reaction reversibility

C) side reaction

D) all of these

61 / 72

A sample of 0.7 moles of metal ‘M’ reacts completely with an excess of fluorine to form 45 g of MF2. How many moles of F are present in it?

PMC Practice 17
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 1.4 moles

B) 2.4 moles

C) 2 moles

D) 1.2 moles

62 / 72

4 gram atoms of carbon has a mass of:

63 / 72

What is the percentage by mass of Nitrogen in NH4(NO3)?

40%

50%

35%

30%

64 / 72

To find the number of molecules in a given compound which of the following is employed?

Chromatography

Le-Chatelier's principle

None of thes

65 / 72

Avogadro’s constant is the number of:

PMC 2021 Tested
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Electrons present in 2g of H

B) Atoms in 24g of Mg

C) Atoms in 1g of He

D) Molecules in 35.5g of Chlorine

66 / 72

Formula mass is considered for compounds instead of their molecular mass.

PMC Practice 21
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Metallic

B) Ionic

C) Covalent

D) Polar covalent

67 / 72

The number of neutrons in H2SO4 are ____.

PMC Practice 26
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 5

B) 49

C) 48

D) 44

68 / 72

Molecular ions are produced by passing a high energy electron beam or an x-ray beam through _______.

PMC Practice 21
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Atoms

B) Molecules

C) Gas

D) Solid

69 / 72

An atom is composed of electrons, protons, neutrons and ___.

PMC Practice 22
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Hyperon

B) Neutrino

C) Anti-neutrino

D) All of these options are correct

70 / 72

The relative abundance of isotopes of elements are measured by?

PMC Practice 11
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) Atomic spectroscopy

B) Ionic spectroscopy

C) Mass spectroscopy

D) Mass spectrometry

71 / 72

If 9.8 g of sulfuric acid is dissolved in an excess quantity of water, it will yield _______ moles of hydrogen ion ( H+) and _______ mole of sulphate ions (SO4 -2).

PMC Practice 22
Chemistry
Introduction to Fundamental Concepts of Chemistry
Elimination Tool:

A) 0.1, 0.2

B) 0.1, 0.3

C) 0.2, 0.4

D) 0.2, 0.1

72 / 72

) Which one of the following has no isotope

Hydrogen

Helium

Nitrogen

None

Your score is

The average score is 61%

Importance of Basic Concepts MCQs

Understanding Basic Concepts helps students perform accurate chemical calculations and solve numerical problems confidently. Most exams include calculation-based MCQs from this chapter, especially from the mole concept, stoichiometry, and significant figures. Practicing chapter-wise MCQs improves speed, accuracy, and problem-solving skills, making it easier to score high in competitive exams.

Effective Strategy for Free Preparation

For effective free preparation, students should revise formulas regularly, practice numericals step by step, and solve topic-wise MCQs consistently. Attempting free tests and past paper questions helps identify important patterns and repeated concepts. PLS Academy provides structured MCQs and free resources to support Chemistry Basic Concepts preparation and other Class 11 Chemistry chapters.

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