Ncert Solutions Chemistry Class 11th

14.4 Assertion: As insect resistance of DDT increased, other organic toxins such as Aldrin and Dieldrin were introduced in the market by pesticide industry.

Reason: The repeated use of the same or similar pesticides give rise to pests that are resistant to that group of pesticides thus making the pesticides ineffective.

14.1 Assertion: Atmosphere trapping the sun’s heat near the earth’s surface is called natural greenhouse effect.

Reason: Atmosphere trapping the sun’s heat maintains the temperature and makes the earth perfect for life.

14.9. What are the reactions involved for ozone layer depletion in the stratosphere?

12.2. Assertion: Citric acid is namedso because it is found in citrus fruits.

Reason: Prior to IUPAC system of nomenclature, organic compounds were assigned

names based on their origin or other properties.

12.41. Assertion: In general, π bonds provide the most reactive centres in the molecules containingmultiple bonds.

Reason: The electron charge cloud of the π bond is located above and below the plane of bonding atoms. The electrons being easily available to the attacking reagents.

12.36. In the organic compound CH2 = CH – CH2 – CH2 – C ≡ CH, the pair of hybridised orbitals involved in the formation of: C2 – C3 bond is:

(a) sp – sp² (b) sp – sp³ (c) sp² – sp³ (d) sp³ – sp³
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12.16. For the following bond cleavages, use curved-arrows to show the electron flow and classify each as homolysis or heterolysis. Identify reactive intermediate produced as free radical, carbocation and carbanion.
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12.11. Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation. (a) C₆H₅OH (b) C₆H₅NO₂ (c) CH₃CH=CHCHO (d) C₆H₅—CHO (e) C₆H₅—CH₂ (f) CH₃CH=CHCH₂
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Identify the functional groups in the following compounds