Class 11 Chemistry Chapter 1 Some Basic Concepts of Chemistry MCQs

Class 11 chemistry MCQs with answers are provided here for chapter 1 Some Basic Concepts of Chemistry. These MCQs are based on CBSE board curriculum and correspond to the most recent Class 11 chemistry syllabus. By practicing these Class 11 Multiple choice questions, students will be able to quickly review all of the ideas covered in the chapter and prepare for the Class 11 Annual examinations as well as other entrance exams such as NEET and JEE.

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Most Important Questions From Some Basic Concept Of Chemistry

Class 11 Some Basic Concepts of Chemistry

1. A pure substance which contains only one type of atom is called ————–.

(a) An element

(b) a compound

(c) a solid

(d) a liquid

Ans: (a) An element

Solution: An element is made up of only one type of atom.

2. The smallest particle that can take part in chemical reactions is ————–.

(a) Atom

(b) molecule

(c) Both (a) and (b)

(d) none of these

Ans: (c) Both (a) and (b)

Solution: The smallest particle that can take part in chemical reactions is both an atom and a molecule.

3. Which of the following is a homogeneous mixture?

(a) Mixture of soil and water

(b) Sugar solution

(c) Mixture of sugar, salt and sand

(d) Iodised table salt

Ans: (b) Sugar solution

Solution: Sugar solution is a homogeneous mixture. A homogeneous mixture is a mixture in which the composition is uniform throughout the mixture

4. The significant figures in 0.00051 are ————–.

(a) 5

(b) 3

(c) 2

(d) 26

Ans: (c) 2

Solution: The significant figures in 0.00051 are 2.

5. Formation of CO and CO2 illustrates the law of ————–.

(a) Law of conservation of mass

(b) Law of Reciprocal proportion

(c) Law of Constant Proportion

(d) Law of Multiple Proportion

Ans: (d) Law of Multiple Proportion

Solution: If an element forms more than one compound with another element for a given mass of an element, masses of other elements are in the ratio of small whole numbers.

6. The number of significant figures in 6.02 x 10²³ is ————–.

(a) 23

(b) 3

(c) 4

(d) 26

Ans: (b) 3

Solution: The number of significant figures in 6.02 x 10²³ is 3

7. The prefix 10¹⁸ is ————–.

(a) giga

(b) exa

(c) kilo

(d) mega

Ans: (b) exa

Solution: The prefix 10¹⁸ is exa

8. The mass of an atom of carbon is ————–.

(a) 1g

(b) 1.99 x 10 ^-23 g

(c) 1/12 g

(d) 1.99 x 10²³ g

Ans: (b) 1.99 x 10 ^-23 g

Solution: The mass of an atom of carbon is {12 / (6.02 x 10 ²³)} = 1.99 x 10 ^-23 g

9. A measured temperature on Fahrenheit scale is 200F. What will this reading be on the Celsius Scale?

(a) 40 ℃

(b) 94 ℃

(c) 93.3 ℃

(d) 30 ℃

Ans: (c) 93.3 ℃

Solution: The relationship between Fahrenheit and degree Celsius is: (⁰F) = 9/5 (^oC) +32.

10. Which of the following pairs of gases contains the same number of molecules?

(a) 16 g of O₂ and 14 g of N₂

(b) 6 g of O₂ and 22 g of CO₂

(c) 28 g of N₂ and 22 g of CO₂

(d) 32 g of CO₂ and 32g of N₂

Ans: (a) 16 g of O₂ and 14 g of N₂

Solution: Divide the given mass by its molar mass to get moles, then multiply times 6.022×1023 to get the number of molecules.