MCQs For CBSE Class 11 Some basic concepts of chemistry

1. Which out of the following is not a homogeneous mixture?

Air
Brass
Solution of sugar in water
Smoke

Answer

2. Which out of the following is not a homogeneous mixture?

Air
Brass
Solution of sugar in water
Smoke

Answer

1.The number of significant figures in 0 050 is

(i) 1

(ii) 2

(iii) 3

(iv) 4

2. Which out of the following is not a homogeneous mixture?

(i) Air

(ii) Brass

(iii) Solution of sugar in water

(iv) Smoke

3. A compound has the empirical formula C₂H₃O₂. Its vapour density is 59. Its molecular formula will be

(i) C₂H₃O₂

(ii) C₄H₆O₄

(iii) C₆H₉O₆

(iv) C₈H₁₂O₈

4 The number of molecules present in 8g of oxygen gas are\

(i) 6.22 x 10²³

(ii) 3.011 x 10²³

(iii) 12.044 x 10²³

(iv) 1.55 x 10²³

5. 112 cm³ of hydrogen gas at STP contain

(i) 0.05 mole

(ii) 0.01 mole

(iii) 0.02 g

(iv) 3.011 x 10²² molecules

6. 10 g CaCO₃ on reaction with 0.1 M HCl acid will produce CO₂

(i) 1120 cm³

(ii) 2240 cm³

(iii) 112 cm³

(iv) 224 cm³

7.One litre of a gas is at a pressure of 10^-6 mm of Hg at 25°C. How many molecules are presenting the vessel?

(i) 3.2 x 10⁶

(ii) 3.2 x 10¹³

(iii) 3.2 x 10¹⁰

(iv) 3 x 10⁴

8.Which of the following has the largest number of atoms?

(i) 0.5 g atom of Cu

(ii) 0.635 g of Cu

(iii) 0.25 moles of Cu atom

(iv) 1 g Cu

9. 27 g of Al (at mass = 27) will react with oxygen equal to

(i) 24 g

(ii) 8 g

(iii) 40 g

(iv) 10 g

10. 2.76 g of silver carbonate (at mass of Ag 108) on being heated strongly yields a residue weighing

(i) 2.16 g

(ii) 2.48 g

(iii) 2.32 g

(iv) 2.64 g

11. if 0.5 mol of BaCl₂ is mixed with 0.2 mol of Na₃PO₄, the maximum number of moles of Ba₃(PO₄)₂ that can be formed is

(i) 0.7

(ii) 0.5

(iii) 0.3

(iv) 0.1

12.If 10²¹ molecules are removed from 200 mg of CO₂, then the number of moles of CO₂ left are

(i) 2.88 x 10^-3

(ii) 1.66 x 10^-3

(iii) 4.54 x 10^-3

(iv) 1.66 x 10^-2

13.The number of gram molecules of oxygen in 6.02 x 10²⁴ CO molecules is

(i) 10 g molecules

(ii) 5g molecule

(iii) 1 g molecules

(iv) 0.5 g molecule.

14. One mole of CO₂ contains

(i) 6.02 x 10²³atoms of C

(ii) 6.02 x 10²³atoms of O

(iii) 18.1 x 10²³atoms of CO₂

(iv) 3 g atoms of CO₂

15. Two elements X (atomic weight 75) and Y (atomic weight 16) combine to give a compound having 75.8 % of X. The formula of the compound is

(i) XY

(ii) X₂ X

(iii) XY₂

(iv) X₂Y₃

16. The largest number of molecules is in

(i) 54 g of nitrogen peroxide

(ii) 28 g of carbon dioxide

(iii) 36 g of water

(iv) 46 g of ethyl alcohol

17. The molecular weight of O₂ and SO₂ are 32and 64 respectively. If one litre of O₂ at 15°C and 750 mm contains N molecules, the number of molecules in two litres of SO₂ under the same conditions of temperature and pressure will be

(i) N/2

(ii) N

(iii) 2N

(iv) 4N

18. Five grams of each of the following gases at 87°C and 750mm pressure are taken. Which of them will have the least volume ?

(i) HF

(ii) HCl

(iii) HBr

(iv) HI

19. Which one of the following is the standard for atomic mass?

20. Rearrange the following (I to IV) in the order of increasing masses and choose the correct answer from (i) (ii) (iii) and (iv). Atomic masses: N = 14, O = 16, Cu = 63)

(a) 1 molecule of oxygen

(b) 1 atom of nitrogen

(d) 1 x 10¹⁰ g atomic weight of copper.

(i) b < a < c < d

(ii) d < c < b < a

(iii) b < c < a < d

(iv) c < d < a < b

21. The number of moles of H₂in 0.224 litres of hydrogen gas at STP (273 K,1atm) (assuming ideal gas behavior) is

(i) 1

(ii) 0.1

(iii) 0.01

(iv) 0.001

22. Two container P and Q of equal volume (1litre each) contain 6 g of O₂ and SO₂ respectively at 300 K and 1 atmosphere, then

(i) No. of molecules in P is less than that in Q

(ii) No. of molecules in Q is less than that in P

(iii) No. of molecules in P and Q are same.

(iv) Either (a) or (b)

23. The maximum amount of BaSO₄ precipitated on mixing BaCl₂ (0.5 M) with H₂SO₄ (1M) will correspond to

(i) 0.5 M

(ii)1.0 M

(iii) 1.5 M

(iv) 2.0 M

24. Given the numbers: 161 cm, 0 – 161 cm, 0 – 0161 cm. The number of significant figures for the three numbers are

(i) 3, 4 and 5 respectively

(ii) 3, 3 and 3 respectively

(iii) 3, 3 and 4 respectively

(iv) 3, 4 and 4 respectively

25. Haemoglobin contains 0.33% of iron by weight. The molecular weight of haemoglobin is approximately 67200. The number of iron atoms (at. Wt. of Fe = 56) present in one molecule of haemoglobin is

(i) 6 (ii) 1 (iii) 4 (iv) 2

26. In the reaction 4NH₃(g) + 5O₂ (g) → 4NO(g) + 6 H₂O (J), when1mole of ammonia and 1 mole of O₂ are made to react to completion

(i) 1.0 mole of H₂O is produced

(ii) 1.0 mole of NO will be produced

(iii) all the oxygen will be consumed

(iv) all the ammonia will be consumed

27. The number of molecules in 16 g of methane is

(i) 3.0 x 10²³

(ii) 6.02 x 10²³

(iii)

(iv)

28. 50 ml 10 N H₂SO₄, 25 ml 12 N HCl and 40 ml 5 N HNO₃ were mixed together and the volume of the mixture was made 1000 ml by adding water. The normality of the resultant solution will be:

(i) 1N

(ii) 2N

(iii) 3 N

(iv) 4N

29. The number of atoms in 4.25 g of NH₃ is approximately

(i) 1 x 10²³

(ii) 2 x 10²³

(iii) 4 x 10²³

(iv) 6 x 10²³

30. A molal solution is one that contains 1 mole of a solute in

(i) 1000 g of solvent

(ii) one liter of the solvent