MCQs on Some Basic Concepts of Chemistry

MCQs on Some Basic Concepts of Chemistry

1. Elements X and Y combine to form two compounds XY and X₂Y. Find the atomic weight of X and Y, if the weight of 0.1 moles of XY is 10g and 0.05 moles of X₂Y is 9g

(a) 30, 20

(b) 80, 20

(c) 60, 40

(d) 20, 30

Answer: (b)

2. Which one will have maximum numbers of water molecules?

(a) 18 molecules of water

(b) 1.8 grams of water

(c) 18 grams of water

(d) 18 moles of water

Answer: (d)

3. The number of atoms present in 0.1 moles of a triatomic gas is

(a) 1.806 × 10²³

(b) 1.806 × 10²²

(c) 3.600 × 10²³

(d) 6.026 × 10²²

Answer: (a)

4. Find the volume of O₂ required to burn 1 L of propane completely, measured at 0℃ temperature and 1 atm pressure

(a) 10 L

(b) 7 L

(c) 6 L

(d) 5 L

Answer: (d)

5. A gas X has C_p and C_v ratio as 1.4, at NTP 11.2 L of gas X will contain_______ number of atoms

(a) 1.2 × 10²³

(b) 3.01 × 10²³

(c) 2.01 × 10²³

(d) 6.02 × 10²³

Answer: (d)

6. Which of the species is not paramagnetic?

(a) As⁺

(b) Cl^–

(c) Ne²⁺

(d) Be⁺

Answer: (b)

7. Pressure has the same dimension as ____________

(a) energy per unit volume

(b) energy

(c) force per unit volume

(d) force

Answer: (a)

8. A container has an equal mass of H₂, O₂ and CH₄ at 27℃, the ratio of their volume is

(a) 16:8:1

(b) 8:1:2

(c) 16:1:2

(d) 8:16:1

Answer: (c)

9. There are two chlorides of sulphur S₂Cl₂ and SCl₂. What is the equivalent mass of S in SCl₂

(a) 64.8 g/mole

(b) 32 g/mole

(c) 16 g/mole

(d) 8 g/mole

Answer: (c)

10. Boron exists as two stable isotopes; ¹⁰B(19%) and ¹¹B(81%). Find out the average atomic weight of boron in the periodic table

(a) 10.0

(b) 11.2

(c) 10.2

(d) 10.8

Answer: (d)

11. The mass of carbon-12 atom considered in the definition of a mole is

(a) 0.12g

(b) 0.012 kg

(c) 120 mg

(d) None of these

Answer: (b)

12. Which of the following is a pair of physical and chemical property respectively of a substance

(a) density and acidity

(b) basicity and colour

(c) colour and density

(d) acidity and combustibility

Answer: (a)

13. The normality of 0.3M phosphorous acid is

(a) 0.9

(b) 0.1

(c) 0.6

(d) 0.3

Answer: (c)

14. 3g of an oxide of a metal is converted into chloride and it yielded 5g of chloride. Find the equivalent weight of the metal 

(a) 20

(b) 12

(c) 3.325

(d) 33.25

Answer: (d)

15. 0.32 gm of a metal on treatment with an acid gave 112mL of hydrogen at STP. Calculate the equivalent weight of the metal. 

(a) 24

(b) 11.2

(c) 32

(d) 58

Answer: (c)

16. Which of the following is not a homogenous mixture?

(a) Brass

(b) Air

(c) Smoke

(d) Aqueous solution of sugar

Answer: (c)