#### Model question paper for Basic Concepts of Chemistry and Chemical Calculations

11th Standard

Reg.No. :
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Chemistry

Time : 02:00:00 Hrs
Total Marks : 100

Part - A

15 x 1 = 15
1. Rusting of iron articles is an example of ___________ reaction

(a)

Combustion

(b)

decomposition

(c)

redox

(d)

hydrolysis

2. Identify the correct statement(s) with respect to the following reaction :
Zn + 2HCl $\longrightarrow$ ZnCl2 + H2
(i) Zinc is acting as an oxidant
(ii) Chlorine is acting as a reductant
(iii) Hydrogen is not acting as an oxidant
(iv) Zn is acting as a reductant

(a)

only (ii)

(b)

only (iv)

(c)

both (ii) and (iii)

(d)

both (ii) and (i)

3. Match the list-I with list-II and select the correct answer using the code given below the lists.

 List-I List-II A Cr2O72- 1 +5 B MnO4- 2 +6 C VO3- 3 +3 D FeF63+ 4 +7
(a)
 A B C D 3 1 4 2
(b)
 A B C D 4 3 2 1
(c)
 A B C D 2 4 1 3
(d)
 A B C D 3 2 1 4
4. Match the items in column list-I with relevant items in list-II.

 List-I List-II A Ions having positive charge 1 anion B Ions having negative charge 2 -1 C Oxidation number of fluorine in NaF 3 0 D The sum of oxidation number of all atoms in a neutral molecule 4 cation
(a)
 A B C D 3 4 2 1
(b)
 A B C D 1 2 3 4
(c)
 A B C D 2 3 4 1
(d)
 A B C D 4 1 2 3
5. Assertion (A): Among halogens fluorine is the best oxidant. Reason
(R): Fluorine is the most electronegative atom.

(a)

Both A and R are true and R explains A

(b)

Both A and R are true but R does not explain A

(c)

A is true but R is false

(d)

Both A and R are false

6. Maximum oxidation state is present in the central metal atom of which compound

(a)

CrO2Cl2

(b)

MnO2

(c)

[Fe(CN)6]3-

(d)

MnO

7. The change in the oxidation number of S in H2S and SO2,in the following industrial reaction:
2H2S(g) + SO2(g) $\longrightarrow$ 3S(s) + H2O(g)

(a)

-2 to 0, +4 to 0

(b)

-2 to 0, +4 to -1

(c)

-2 to -1, +4 to 0

(d)

-2 to -1, +4 to -2

8. In which of the following reactions, hydrogen peroxide acts as an oxidising agent?

(a)

I2+ H2O2 + 20H- $\longrightarrow$ 21- + 2H2O + O2

(b)

PbS + 4H2O2 $\longrightarrow$ PbSO4 + 4H2O

(c)

2MnO4-+ 3H2O2 $\longrightarrow$ 2MnO2 + 3O2 + 2H2O + 2OH-

(d)

HOCI + H2O2 $\longrightarrow$ H2O+ + Cl- + O2

9. Identify the redox reaction taking place in a beaker.

(a)

Zn(s)+ Cu2+(aq) $\longrightarrow$ Zn2+(aq) + Cu(s)

(b)

Cu(s) + 2Ag+(aq) $\longrightarrow$ Cu2+(aq) + 2Ag(s)

(c)

Cu(s) + Zn2+(aq) $\longrightarrow$ Zn(s) + cu2+ (aq)

(d)

2Ag(s) + cu2+(aq) $\longrightarrow$ 2Ag+aq + Cu(s)

10. Consider the following statements
i) Matter possesses mass.
ii) 22-carat gold is a mixture.
iii) Dry ice is a compound.
Which of the following statement(s) given above is/ are correct?

(a)

1 & 3

(b)

Only 1

(c)

1 & 2

(d)

1,2, & 3

11. Match the list I with List II and select the correct answer using. the code given below the lists.

 List I List II A Diamond 1 Heterogeneous mixture B Aerated drinks 2 Element C Distilled water 3 Homogeneous mixture D Sand 4 Compound
(a)
 A B C D 2 3 4 1
(b)
 A B C D 4 3 1 2
(c)
 A B C D 3 1 4 2
(d)
 A B C D 2 1 4 3
12. The solid state of matter is converted into gas by

(a)

sublimation

(b)

deposition

(c)

freezing

(d)

condensation

13. The characteristic feature of orderly arrangement of molecules belongs to

(a)

Solids

(b)

Liquid

(c)

Gases

(d)

None of these

14. Which among the following statement(s) describe an element?
i) It is a pure substance which could be split into two or more simpler substance.
ii) It is a pure substance which cannot be split into simpler substance
iii) It's composition is not uniform
iv) All the above

(a)

only (iv)

(b)

only (ii)

(c)

(ii) and (iii)

(d)

(i) and (iii)

15. Which form of based on physical characteristics possess neither definite volume nor definite shape?

(a)

Solids

(b)

Liquids

(c)

Gases

(d)

Both (a) and (b)

16. Part - B

10 x 2 = 20
17. Calculate the molar mass of the following compounds. -Sulphurci  Acid [H2SO4]

18. Balance the following equations by ion electron method $Zn+{ NO }_{ 3 }^{ - }\longrightarrow { Zn }^{ 2+ }+No$

19. Give a brief account of classification of matter.

20. Why atomic masses are called as relative atomic masses?

21. Define relative atomic mass

22. Give examples for the following redox reaction "Disproportionation."

23. Give the relationship between the number of mole of the substance and its gram molecular mass.

24. Calculate the equivalent masses of the following - HCl

25. Calculate the equivalent masses of the following - HNO3

26. Calculate the equivalent masses of the following - Oxalic acid H2C2O4

27. Calculate the equivalent masses of the following - Crystalline Oxalic acid, H2C2O4 , 2H2O

28. Calculate the equivalent masses of the following - Ferrous Sulphate

29. Part - C

15 x 3 = 45
30. MnO42- undergoes disproportionation reaction in acidic medium but MnO4- does not. Give reason.

31. 2Cu2S + 3O2 $\longrightarrow$ 2Cu2O + 2SO2
(i) In this reaction which substance is getting oxidised and which substance is getting reduced?
(ii) Name the oxidising and reducing agents.

32. How would you know whether a redox reaction is taking place in an acidic, alkaline or neutral medium?

33. What is the most essential conditions that must be satisfied in a redox reaction?

34. Zn rod is immersed in CuSO4 solution. What will you observe after an hour? Explain you observation in terms of the redox reaction.

35. Which one of the two, ClO2- or ClO4- shows disproportionation reaction and why?

36. 'X' is an impure substance. Is it an element, compound or mixture?

37. Why is distilled water a compound whereas tap water is a mixture?

38. Why is air sometimes considered as a heterogeneous mixture?

39. By applying the knowledge of chemical classification, classify each of the following into elements, compounds or mixtures
(i) Sugar
(ii) Sea water
(iii) Distilled water
(iv) Carbon dioxide
(v)  Copper wire
(vi) Table salt
(vii) Silverplate
(viii) Naphthalene balls

40. Matter is defined as anything that has mass and occupies space. All matter is composed of atoms

41. Write a note on the differences between elements and compounds

42. How will you classify matter based on physical state?

43. Explain the classification of matter based on chemical composition.

44. Calculate the number of atoms in the following.52 moles of He.

45. Calculate the mass of the following: 1 atom of silver

46. Calculate the mass of the following: 1 molecule of water.

47. How much mass (in gram units) is represented by the following?
0.2 mol of NH3

48. Part - D

Answer any 4 of the following questions

4 x 5 =20
49. Distinguish between the following.
(i) Atomic and molecular mass
(ii) Atomic mass and atomic weight
(iii) Empirical and molecular formula
(iv) Moles and molecules.

50. In a reaction, A + B2 $\longrightarrow$ AB2, identify the limiting reagent if any in the following reaction mixtures
(i) 300 atoms of A + 200 molecules of B
(ii) 2 moles of A + 3 moles of B
(iii) 100 atoms of A + 100 molecules of B
(iv) 5 moles of A + 2.5 moles of B
(v) 2.5 moles of A + 5 moles of B

51. Balance the following equations by oxidation number method.
NH3 + F2 ⟶ HF + N2

52. Balance the following equations by oxidation number method.
K2Cr2O7 + FeSO4 + H2SO4 ⟶ K2SO4 + Cr2(SO4)3 + Fe2(SO4)3 + H2O

53. Balance the following equation by oxidation number method.
C6H6 + O2$\rightarrow$CO2 + H2O

54. Balance the following equation by oxidation number method.
KMnO4 + HCI $\rightarrow$ KCl + MnCl2 + H2O + Cl2