Question

Class 11 chemistry MCQ Question of Some Basic Concepts of Chemistry with Answers?

Answer 1

Class 11 Chemistry MCQ Questions Some Basic Concepts of Chemistry with Answers have been organized primarily based totally on the maximum current examination pattern and syllabus. Chemistry is virtually a big subject that incorporates numerous subjects and sub-topics. In the case of board examinations and competitive exams, the usual of the questions has risen ten-fold from the past. 

Therefore, attempting just some basic chemistry questions won’t be of lots of help. We have provided Chemistry MCQ Questions for class 11 Chemistry with Answers to help college students know the idea alright.

Here is the list of topics covered from that MCQ Questions are given for practice: -

• Nature of matter
• Properties of matter and their measurement
• The International System of Units (SI)
• Mass and Weight
• Uncertainty in measurement
• Scientific notation
• Significant figures
• Dimensional analysis
• Laws of chemical combinations
• Dalton’s atomic theory
• Atomic and molecular masses
• Percentage composition
• Empirical formula for molecular formula
• Stoichiometry and stoichiometric calculations

class 11 Some basic concepts of chemistry MCQ Questions will help you to check your preparation level.

Practice MCQ Questions for class 11 Chemistry Chapter-Wise

1. Approximate atomic weight of an element is 26.89. If its equivalent weight is 8.9, the exact atomic weight of element would be

(a) 26.89
(b) 8.9
(c) 17.8
(d) 26.7

2. What is the normality of a 1 M solution of H₃PO₄

(a) 0.5 N
(b) 1.0 N
(c) 2.0 N
(d) 3.0 N

3. The total number of ions present in 111 g of CaCl₂ is

(a) One ions
(b) Two ions
(c) Three ions
(d) Four ions

4. Under similar conditions of pressure and temperature, 40 ml of slightly moist hydrogen chloride gas is mixed with 20 ml of ammonia gas, the final volume of gas at the same temperature and pressure will be

(a) 100 ml
(b) 20 ml
(c) 40 ml
(d) 60 ml

5. Which of the following cannot give iodometric titrations

(a) Fe³⁺
(b) Cu²⁺
(c) Pb²⁺
(d) Ag⁺

6. The significant figures in 3400 are

(a) 2
(b) 5
(c) 6
(d) 4

7. A symbol not only represents the name of the element but also represents

(a) Atomic Mass
(b) Atomic Number
(c) Atomicity
(d) Atomic Volume

8. The S.I unit of temperature is :

(a) Kelvin
(b) Celsius
(c) Fahrenheit
(d) Centigrade

9. A mixture of sand and iodine can be separated by

(a) sublimation
(b) crystallisation
(c) distillation
(d) fractionation

10. Which of the following is an example of a heterogeneous substance?

(a) Candle
(b) Pieces of copper
(c) Table salt
(d) Bottled water

11. Which one of these is not a pure compound?

(a) Sucrose solution
(b) H₂O₂
(c) O₃
(d) H₂O

12. Which one of the following set of units represents the smallest and largest amount of energy respectively?

(a) eV and L-atm
(b) erg and cal
(c) J and erg
(d) cal and eV

13. The number of significant figures for the three numbers 161 cm, 0.161 cm, 0.0161 cm are

(a) 3,3 and 3 respectively
(b) 3,4 and 4 respectively
(c) 3,4 and 5 respectively
(d) 3,3 and 4 respectively

14. Difference in density is the basis of

(a) gravity separation
(b) molecular sieving
(c) ultrafiltration
(d) molecular attraction

15. Which of the following statements about a compound is incorrect?

(a) A compound retains the physical properties of its constituent elements
(b) The ratio of atoms of different elements in a compound is fixed
(c) A compound cannot be separated into its constituent elements by physical methods of separation
(d)  A molecule of a compound has atoms of different elements

16. The product of atomic mass and specific heat of metal is approximately 6.4. This was given by:

(a) Dalton's law
(b) Avogadro's law
(c) Newton's law
(d) Dulong Petit's law

17. Which of the following pairs of gases contains the same number of molecules:-

(a) 16g of O₂ and 14g of N₂
(b) 8g of O₂ and 22g of CO₂
(c) 28g of N₂ and 22g of CO₂
(d) 32g of O₂ and 32g of N₂

18. At S.T.P. the density of CCl₄ vapour in g/L will be nearest to

(a) 6.87
(b) 3.42
(c) 10.26
(d) 4.57

19. 1 mole of K₄[Fe(CN)₆] contain carbon = 6 g atoms 0.5 mole of K₄[Fe(CN)₆] contain carbon = 3g atomsThe mass of carbon present in 0.5 mole of K₄[Fe(CN)₆] is

(a) 1.8 g
(b) 18 g
(c) 3.6 g
(d) 36 g

20.  The number of moles of BaCO3 which contains 1.5 moles of oxygen atoms is

(a) 0.5
(b) 1
(c) 3
(d) 6.02 ×10²³

_21. The empirical formula of an organic compound containing carbon and hydrogen is CH₂. The mass of one litre of this organic gas is exactly equal to that of one litre of N₂. Therefore, the molecular formula of the organic gas is

(a) C₂H₄
(b) C₃H₆
(c) C₆H₁₂
(d) C₄H₈

22. Which is not a unit of pressure:

(a) Bar
(b) N/m²
(c) Kg/m²
(d) Torr

23. One fermi is

(a) 10^–13 cm
(b) 10^–12 cm
(c) 10^–15 cm
(d) 10^–10 cm

24. Carbon and oxygen combine to form two oxides, carbon monoxide and carbon dioxide in which the ratio of the weights of carbon and oxygen is respectively 12 :16 and 12 : 32. These figures illustrate the:

(a)  Law of multiple proportions
(b)  Law of reciprocal proportions
(c)  Law of conservation of mass
(d)  Law of constant proportions

25. Among the following the temperature dependent parameter is -

(a) Molarity
(b) Mole fraction
(c) Weight percentage
(d)  Molality

Answer 2

1. Answer: (d) 26.7

Explanation: Atomic weight = (Equivalent weight \(\times\) Valency)

=(8.9 \(\times\) 3)

= 26.7

2. Answer : (d) 3.0 N

Explanation: H₃PO₄ is tribasic

So N = 3M

= 3 \(\times\) 1 = 3

3. Answer : (c) Three Mole

Explanation: Molecular weight of CaCl₂ = 111g/mol 

Ions in one calcium chloride molecule = Ca⁺² + 2Cl^- = 3 ions

4. Answer : (b) 20 ml

Explanation: NH₃ + HCl→ NH₄Cl

According to the given question, 1 ml NH₃ reacts with 1 ml HCl to produce 1 ml of NH₄Cl.So, 20 ml of ammonia reacts with 20 ml of HCl to produce 20 ml of resultant NH₄Cl. The rest of HCl will stay unreacted.

5. Answer : (c) Pb²⁺

Explanation: Atom in highest oxidation state can oxidize iodide to liberate I₂ which is volumetrically measured by iodometric titration using hypo.

2I^–→I₂

Pb⁺² → Lowest oxidation state cannot oxidise iodide to I₂

6. Answer : (b) 5

Explanation: Exponential form of 3400 = 3.4 \(\times\) 10³

∵ All non-zero digits are significant numbers.

∴ 3400 has 2 significant numbers

7. Answer : (c) Atomicity

Explanation: Symbol of an element represents the name along with the number of same atoms in room condition, which is its atomicity, of that element.

8. Answer : (a) Kelvin

Explanation: The kelvin is the SI unit of thermodynamic temperature, and one of the seven SI base units. Unusually in the SI, we also define another unit of temperature, called the degree Celsius (^°C).

9. Answer : (a) sublimation

Explanation: Sublimation separates a mixture of solids, one of which changes directly from a solid to vapour on heating without going through the liquid state. This change is called sublimation. 

10. Answer : (a) Candle

Explanation: The type of mixture in which the constituent elements are different and are not uniformly distributed, it is called heterogeneous substance.

11. Answer : (a) Sucrose solution

Explanation: Sugar solution is a mixture and made up of different kinds of molecules. So it is not a pure substance.

12. Answer : (a) eV and L-atm

Explanation: Smallest and largest amount of energy respectively eV and L-atm.

1eV = 1.6 \(\times\) 10⁻¹⁹J

1L−amt = 101.325J

13. Answer : (a) 3,3 and 3 respectively

Explanation: (i) All non-zero digits are significant.

(ii) Non-zero digits to the right of the decimal point are significant.

(iii) Zeroes to the left of the first non-zero digit in a number are not significant.

14. Answer : (a) gravity separation

Explanation: In gravity separation difference in density of particles is employed In molecular attraction, mainly exchange of cations to anions among given two molecules.

15. Answer : (c) A compound cannot be separated into its constituent elements by physical methods of separation

Explanation: A compound is a pure substance containing two or more than two elements combined together in a fixed proportion by mass and which can be decomposed into its constituent elements by suitable chemical methods. Further, the properties of a compound are quite different from the properties of constituent elements.

16. Answer : (d) Dulong Petit's law

Explanation: According to Dulong Petit's law, the product of atomic mass and specific heat of any element is constant and it is equals to 6.4.

17. Answer : (a) 16g of O₂ and 14g of N₂

Explanation: 16g O₂ has number of moles = 16/32 = 1/2

14g N₂ has number of moles = 14/28 = 1/2

Hence, no of moles are same. So number of molecules are also same.

18. Answer : (a) 6.87

Explanation: 1 mole CCl₄ vapours = 12 + 4 \(\times\) 35.5 = 154g

At STP, volume of 1 mole of a gas = 22.4 L

Thus, 154g = 22.4L

∴ Density of CCl4 vapours =154/22.4 gL⁻¹

= 6.87gL⁻¹

19. Answer : (d) 36 g

​​Explanation: 1 mole of K₄[Fe(CN)₆] contain carbon = 6 g atoms

0.5 mole of K₄[Fe(CN)₆] contain carbon = 3g atoms

Mass of carbon in grams \(=(12g)\times\frac{(3\;g\;atoms)}{(1g\;atom)}\)

= 36 g

20. Answer : (a) 0.5

​​Explanation: 3 moles of oxygen is that in 1 mole of BaCO₃

∴1.5 moles of oxygen is that in mole of BaCO₃

_{\(=\frac{1}{3}\times1.5=\frac{1}{2}\)}

_{= 0.5}

21. Answer :(a) C₂H₄

​​Explanation: Mass of 1 L of gas = mass of 1 L of N₂ according to Avogadro’s hypothesis.

Molecular masses will also be equal, then molecular mass of the gas=28. Hence formula is C₂H₄ (2 ×12 + 4 × 1 = 28).

22. Answer : (c) Kg/m²

​​Explanation: Pressure is force per unit area so Kg/m² cannot be a unit of pressure.

23. Answer : (a) 10^–13 cm

​​Explanation: A Fermi is equivalent to a femtometre, and it is the older non–SI measurement unit of length, It is named in honour of Italian physicist Enrico Fermi. 1Fm = 10^{– 15}m = 10^–13 cm.

24. Answer : (a)  Law of multiple proportions

​​Explanation: According to the law of multiple proportions, when two elements combine with each other to form two or more than two compounds, the masses of one of the elements which combine with a fixed mass of the other, bear a simple whole number ratio.

25. Answer : (a) Molarity

​​Explanation: Molarity and normality are temperature dependent because they involve volume of solutions. Volume is dependent on temperature. Molality, mole fraction and weight percentage does not depend on temperature because they involve masses of solute and solvent.

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