" /> -->

#### Basic Concepts of Chemistry and Chemical Calculations important one mark questions

11th Standard

Reg.No. :
•
•
•
•
•
•

Chemistry

Time : 00:40:00 Hrs
Total Marks : 50

Part - A

50 x 1 = 50
1. The oxidation state of a element in its uncombined state is

(a)

zero

(b)

+1

(c)

-1

(d)

none

2. Fe2 + $\longrightarrow$ Fe3+ + e- is a ________ reaction.

(a)

redox

(b)

reduction

(c)

oxidation

(d)

decomposition

3. Assertion: Fluorine has an oxidation state of - 1in all its compounds.
Reason: Fluorine is the most electronegative element of the periodic table.

(a)

Both assertion and reason are correct and the reason is the correct explanation for the assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for the assertion

(c)

Assertion is true but reason are false.

(d)

Both assertion and reason are false.

4. The oxidation number of oxygen in O2 is _______________

(a)

0

(b)

+1

(c)

+2

(d)

-2

5. The oxidation number of hydrogen in LiH is _____________

(a)

+1

(b)

-1

(c)

+2

(d)

-2

6. The oxidation number of Cr in Cr2O72- __________ is

(a)

+6

(b)

-6

(c)

+7

(d)

-7

7. Among the three metals, zinc, copper and silver, the electron releasing tendency decreases in the following order.

(a)

zinc >silver >copper

(b)

zinc >copper >silver

(c)

silver > copper >zinc

(d)

copper > silver > zinc

8. Consider the following statements :
(i) Oxidation number of He = zero
(ii) Increase in oxidation number results in reduction.
(iii) The substance undergoing the increase in oxidation number is reducing agent.
Which among the above statement(s) is/are correct?

(a)

only (i)

(b)

(ii) and (iii)

(c)

(i) and (iii)

(d)

only (ii)

9. Rusting of iron articles is an example of ___________ reaction

(a)

Combustion

(b)

decomposition

(c)

redox

(d)

hydrolysis

10. Identify disproportionation reaction

(a)

CH4 + 2O2 $\longrightarrow$ CO2+ 2H2O

(b)

CH4 + 4Cl2 $\longrightarrow$ CCl4 + 4HCI

(c)

2F2+ 2OH $\longrightarrow$ 2F-+ OF2+ H2O

(d)

2NO2 + 2OH- $\longrightarrow$ NO-2 + NO-3 + H2O

11. Which of the following statement(s) is/are not true about the following decomposition reaction.
2KClO3 $\longrightarrow$ 2KCl + 3O2
(i) Potassium is undergoing oxidation
(ii) Chlorine is undergoing oxidation
(iii) Oxygen is reduced
(iv) None of the species are undergoing oxidation and reduction.

(a)

only (iv)

(b)

(i) and (iv)

(c)

(iv) and (iii)

(d)

All of these

12. 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)

13. 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
14. 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
15. 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

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

(a)

CrO2Cl2

(b)

MnO2

(c)

[Fe(CN)6]3-

(d)

MnO

17. Identify the correct statements with reference to the given reaction
P4 + 3OH- + 3H2O $\longrightarrow$ PH3 + 3H2PO2-
(i) Phosphorous is undergoing reduction only
(ii) Phosphorous is undergoing oxidation only
(iii) Phosphorous is undergoing both oxidation and reduction.
(iv) Hydrogen is undergoing neither oxidation nor reduction.

(a)

only (iii)

(b)

both (iii) and (iv)

(c)

only (i)

(d)

None of these

18. Assertion (A): In the reaction between potassium permanganate and potassium iodide, permanganate ions act as oxidising agent.
Reason (R): Oxidation state of manganese changes from +2 to +7 during the reaction.

(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

19. 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

20. 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

21. 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)

22. 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

23. 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
24. The solid state of matter is converted into gas by

(a)

sublimation

(b)

deposition

(c)

freezing

(d)

condensation

25. Identify the incorrect statement about a compound.

(a)

A molecule cannot be separated into its constituent elements by physical methods of separation

(b)

A molecule of a compound has atoms of different elements

(c)

A compound retains the physical properties of its constituent element

(d)

The ratio of atoms of different elements in a compound is fixed

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

(a)

Solids

(b)

Liquid

(c)

Gases

(d)

None of these

27. 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)

28. 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)

29. Match list I with list II and identify the correct code.

List I List II
A Bronze 1 Element
B Table Salt 2 Homogeneous mixture
C Gold 3 Alloy
D Petrol 4 Compound
(a)
 A B C D 1 4 2 3
(b)
 A B C D 3 4 1 2
(c)
 A B C D 2 3 4 1
(d)
 A B C D 4 2 3 1
30. Atoms are too small with a diameter of 10-10 m and weigh approximately

(a)

10-27 kg

(b)

10-27 g

(c)

10-31 kg

(d)

10-31

31. 1 amu (or) 1 u $\approx$

(a)

1.6605 x 10-25 kg

(b)

1.6605 x 10-26 kg

(c)

1.6605 x 10-27 kg

(d)

1.6605 x 10-28 kg

32. 12 g of carbon-12 contains_____carbon atoms

(a)

6.022 x 1023

(b)

6

(c)

12

(d)

12.022 x 10-23 kg

33. Statement I: an Equivalent mass of Mg is  determined by Oxide Method
Statement II: Molecular mass is calculated using vapour density

(a)

Both the statements are individually true

(b)

Both the statements are individually true and statement II is the correct explanation of statement 1.

(c)

Statement I is true but statement IIis false.

(d)

Statement Iis false but statement IIis true

34. The volume occupied by any gas at S.T.P. is_____

(a)

22.4litres

(b)

2.24litres

(c)

224 litres

(d)

0.224 litres

35. One mole of Sulphuric acid contains _______oxygen atoms

(a)

4 x 1023

(b)

4 x 6.023 x 10-23

(c)

4 x 6.023 x 1023

(d)

4 x 6.023 x 1032

36. Unit of Avogadro's number is

(a)

mol

(b)

g

(c)

mol -1

(d)

No unit

37. Atomicity of nitrogen is

(a)

1

(b)

2

(c)

3

(d)

Zero

38. Assertion: An element has a fractional atomic mass.
Reason: An element exist as isotope

(a)

Both assertion and reason are correct and reason is the correct explanation for the assertion

(b)

Both assertion and reason are correct but reason is not the correct explanation for an assertion

(c)

Assertion is true but reason is false.

(d)

Both assertion and reason are false

39. The empirical formula and molecular mass of a compound are CH2O and 180g respectively. What will be the molecular formula of the compound?

(a)

C9H190

(b)

CH2O

(c)

C6H12O6

(d)

C2H4O2

40. One 'U' stands for the mass of

(a)

An atom of carbon-12

(b)

1/12th of the carbon-12

(c)

1/12th of a hydrogen atom

(d)

One atom of any of the element

41. What will be the basicity of H3BO3, which is not a protic acid?

(a)

One

(b)

Two

(c)

Three

(d)

Four

42. In the reaction to NH3 + H2$\longrightarrow$ ${ NH }_{ 4 }^{ + }+O\overline { H }$, NH3 is acidic in. the reason for its acidic is_____

(a)

Acceptance of one H+from water

(b)

A release of one OH-ion

(c)

Due to the nitrogen atom

(d)

All the above

43. Match the following prefixes with their multiples.

Equivalent Mass(E) Molecular Mass (M)
A EkMnO4 (Acidic) 1 M/2
B EkMnO4 (Neutral) 2 M
C EH3PO2 3 M/3
4 EH3PO3 4 M/5
(a)
 A B C D 4 3 2 1
(b)
 A B C D 4 2 1 3
(c)
 A B C D 3 4 2 1
(d)
 A B C D 3 1 4 2
44. Calculate the percentage of N in ammonia molecule.

(a)

121.42%

(b)

28.35%

(c)

82.35%

(d)

28.53%

45. If a beaker holds 576g of water, what will be the gram molecules of water in that beaker?

(a)

23 gram molecule

(b)

23%

(c)

32%

(d)

32 gram molecule

46. Assertion: The atomic masses of most of the elements. are in the fraction.
Reason:  The atomic mass represents the ratio of the average mass of the atom to one avogram.

(a)

Both assertion and reason are correct and the reason is the correct explanation for assertion

(b)

Both assertion and reason are correct but the reason is not the correct explanation for an assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

47. Assertion: The number of oxygen atoms in 16g of oxygen and 16g of ozone is same
Reason Each of the species represent 1g atom of oxygen

(a)

Both assertion and reason are correct and the reason is the correct explanation for an assertion

(b)

Both assertion and reason are correct but a reason  is not the correct explanation for assertion

(c)

Assertion is true but reason are false.

(d)

Both assertion and reason are false

48. Assertion: The ash produced by burning paper in air is lighter than the original mass of paper.
Reason: he residue left after combustion of a chemical entity is always lighter

(a)

Both assertion and reason are correct and reason is the correct explanation for assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

49. Assertion: Oxalic acid is a dibasic acid
Reason: It contains two basic radicals

(a)

Both assertion and reason are correct and reason is the correct explanation for assertion.

(b)

Both assertion and reason are correct but reason is not the correct explanation for assertion

(c)

Assertion is true but reason are false

(d)

Both assertion and reason are false

50. How many moles of magnesium phosphate Mg3(PO4)2 Will Contain 0.25 moles of oxygen atoms?

(a)

0.02

(b)

3.125 x 10-2

(c)

1.25 x 10-2

(d)

2.5 x 10-2