CBSE 11TH CHEMISTRY (Test 2)



Tag: cbse 11th chemistry
Q.1
The effect of undesirable changes in the environment causing harm to living beings is termed as:
A. environmental chemistry
B. Environmental pollution
C. environmental studies
D. environmental biology
Answer : Option B
Explaination / Solution:

Environmental pollution is the harmful effect of undesirable changes caused by substances of chemical, biological or human origin.

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Q.2
Hydrocarbons are formed by :
A. Incomplete combustion of fuel used in automobiles
B. Complete combustion of fossil fuel
C. Combustion of fuel in automobiles, at high temperatures
D. Complete combustion of carbon
Answer : Option A
Explaination / Solution:

Hydrocarbons are formed by incomplete combustion of fossil fuels used in automobiles. When they undergo incomplete combustion, they are partially oxidised and produce other fragments of hydrocarbons along with CO and C.

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Q.3
This process in which nutrient enriched water bodies support a dense plant population, which kills animal life by depriving it of oxygen and results in subsequent loss of biodiversity, is called as :
A. Eutrophication
B. Troposphere effect
C. Increase in green house gas
D. Mesosphere effect
Answer : Option A
Explaination / Solution:

Eutrophication is the process in which nutrient enriched water bodies support a dense plant population, which kills animal life by consuming oxygen and depriving them of it.

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Q.4
The death of Scandinavian forests was blamed on:
A. Pollution from Scandinavian power stations
B. Tree surgeons
C. Pollution from UK power stations
D. The Chernobyl disaster
Answer : Option C
Explaination / Solution:

The death of Scandinavian forests was blamed on Pollution from UK power stations

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Q.5
Carbon dioxide and oxygen levels are maintained by:
A. Photosynthesis
B. Respiration
C. Perspiration
D. Photosynthesis and respiration
Answer : Option D
Explaination / Solution:

Carbon dioxide and oxygen levels are maintained by Photosynthesis by plants and respiration by organisms.

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Q.6
Saturated Hydrocarbons contain
A. ionic bonds
B. triple bonds
C. single bonds
D. double bonds
Answer : Option C
Explaination / Solution:

saturated hydrocarbons  are the compounds in which there is a single bond between the carbon atoms.They are also called alkanes and have the general formula CnH2n+2

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Q.7
In the alkene having IUPAC name 3-Methyl-1-butene the double bond lies on carbon atom numbered
A. 2
B. 1
C. 3
D. 4
Answer : Option B
Explaination / Solution:

‘1’ is written before butene which indicates that the position of the double bond is on carbon 1.The structure of the compound is: CH2=CHCH(CH3)CH3

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Q.8
The unusual behavior of benzene is explained by
A.  hybridization
B. kekule structure
C.  hybridization
D. delocalized π electron cloud
Answer : Option D
Explaination / Solution:

resonance stabilisation explains the unusual stability of benzene.There is pi electron delocalisation in the ring which enhances the stability of the molecule.

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Q.9
Arrange the following hydrogen halides in order of their decreasing reactivity with propene.
A. HBr > HI > HCl
B. HI > HBr > HCl
C. HCl > HBr > HI
D. HCl > HI > HBr
Answer : Option B
Explaination / Solution:

As we move from Cl to I,the atomic size increases,bond length increases,bond strength decreases,hence it becomes easier to release halogen and hence the order.I- is the a better leaving group.

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Q.10
A dibromo derivative of an alkane reacts with sodium metal to form an alicyclic hydrocarbon. The derivative is ______.
A. 1, 1-dibromopropane
B. 2, 2-dibromobutane
C. dibromoethane
D. 1, 4-dibromobutane
Answer : Option D
Explaination / Solution:

1,4 - dibromobutane ( ie. a  dibromoderivative of an alkane , butane)   when reacted withl  in ethereal solution produces alicyclic hydrocarbon, Cyclobutane  as per following reaction.

Therefore , the dibromo-derivative of alkane is identified   as 1 , 4-dibromobutane.


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