#### 11th Standard Chemistry Basic Concepts of Chemistry and Chemical Calculations English Medium Free Online Test One Mark Questions 2020 - 2021

11th Standard

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Chemistry

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. An element X has the following isotopic Composition 200X = 90%, 199X = 8% and 202X = 2% The Weighted average atomic mass of the element X is closet to

(a)

201 u

(b)

202 u

(c)

199 u

(d)

200 u

2. When 22.4 litres of H2(g) is mixed with 11.2 litres of Cl2(g), each at 273 K at 1 atm the moles of HCl (g), formed is equal to

(a)

2 moles of HCI (g)

(b)

0.5 moles of HCI (g)

(c)

1.5 moles of HCI (g)

(d)

1 moles of HCI (g)

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

(a)

redox

(b)

reduction

(c)

oxidation

(d)

decomposition

4. 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

5. 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
6. If Avogadro number were changed from 6.022 x 1023to 6.022 x 1020, this would change

(a)

the ratio of chemical species to each other in a balanced equation

(b)

the ratio of elements to each other in a compound

(c)

the definition of mass in units of grams

(d)

the mass of one mole of carbon

7. What is the mass of precipitate formed when 50 ml of 8.5 % solution of AgNO3 is mixed with 100 ml of 1.865 % potassium chloride solution?

(a)

3.59g

(b)

7g

(c)

14 g

(d)

28 g

8. Which of the following is/are true with respect to carbon -12

(a)

relative atomic mass is 12 u

(b)

the oxidation number of carbon is +4 in all its compounds.

(c)

1 mole ofcarbon-12 contain 6.022 x 1022 carbon atoms.

(d)

All of these

9. 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

10. 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
11. 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

12. 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)

13. 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

14. 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

15. 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

16. 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

17. Give an example of molecule in which the ratio of the molecular formula is six times the empirical formula.

(a)

C6H12O6

(b)

CH2O

(c)

CH4

(d)

NA2CO3

18. The formula weight of ethanol (C6H5OH) is ____________.

(a)

56.5 amu

(b)

16 amu

(c)

60 amu

(d)

46 amu

19. The mass of an atom of nitrogen is _______________.

(a)

$\frac { 14 }{ 6.023\times { 10 }^{ 23 } }$

(b)

$\frac { 28 }{ 6.023\times { 10 }^{ 23 } }$

(c)

$\frac { 1 }{ 6.023\times { 10 }^{ 23 } }$

(d)

14 amu

20. The oxidation number of carbon in CH3 - CH2OH is _______________.

(a)

+2

(b)

-2

(c)

0

(d)

+4