11th Chemistry - Book Back Answers - Unit 11 - English Medium Guides

 

 

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Tamil Nadu Board 11th Standard Chemistry - Unit 11 : Book Back Answers and Solutions

    This post covers the book back answers and solutions for Unit 11 – Chemistry from the Tamil Nadu State Board 11th Standard Chemistry textbook. These detailed answers have been carefully prepared by our expert teachers at KalviTips.com.

    We have explained each answer in a simple, easy-to-understand format, highlighting important points step by step under the relevant subtopics. Students are advised to read and memorize these subtopics thoroughly. Once you understand the main concepts, you’ll be able to connect other related points with real-life examples and confidently present them in your tests and exams.

    By going through this material, you’ll gain a strong understanding of Chemistry Unit 11 along with the corresponding book back questions and answers (PDF format).

Question Types Covered:

• 1 Mark Questions: Choose the correct answer, Fill in the blanks, Identify the correct statement, Match the following 
• 2 Mark Questions: Answer briefly 
• 3, 4, and 5 Mark Questions: Answer in detail

All answers are presented in a clear and student-friendly manner, focusing on key points to help you score full marks.

All the best, Class 11 students! Prepare well and aim for top scores. Thank you!

Unit 11 :Fundamentals of Organic Chemistry

I. Choose the best answer.

1.Select the molecule which has only one π bond.

a) CH₃– CH = CH – CH₃
b) CH₃– CH = CH – CHO
c) CH₃– CH = CH – COOH
d) All of these
Answer Key:
a) CH₃– CH = CH – CH₃
 
2.In the hydrocarbon
$$
the state of hybridisation of carbon 1,2,3,4 and 7 are in the following sequence.
a) sp, sp, sp³, sp², sp³
b) sp2, sp, sp³, sp², sp³
c) sp, sp, sp², sp, sp³
d) none of these
Answer Key:
a) sp, sp, sp³, sp², sp³
 
3.The general formula for alkadiene is
a) C_nH2_n
b) C_nH2_n-1
c) C_nH2_n-2
d) C_nH_n-2
Answer Key:
c) C_nH2_n-2
 
4.Structure of the compound whose IUPAC name is 5,6 - dimethylhept - 2 -ene is 

Answer Key:

 

 

5.The IUPAC name of the Compound is

a) 2,3 - Diemethylheptane

b) 3- Methyl -4- ethyloctane
c) 5-ethyl -6-methyloctane
d) 4-Ethyl -3 - methyloctane.
Answer Key:
d) 4-Ethyl -3 - methyloctane
 
6.Which one of the following names does not fit a real name?
a) 3 – Methyl –3–hexanone
b) 4–Methyl –3– hexanone
c) 3– Methyl –3– hexanol
d) 2– Methyl cyclo hexanone.
Answer Key:
a) 3 – Methyl –3–hexanone
 
7.The IUPAC name of the compound CH₃–CH= CH – C ≡ CH is
a) Pent - 4 - yn-2-ene
b) Pent -3-en-l-yne
c) pent – 2– en – 4 – yne
d) Pent – 1 – yn –3 –ene
Answer Key:
b) Pent -3-en-l-yne
 
8.IUPAC name of is $\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{-}\underset{\underset{{\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}}{\mathbf{|}}}{\overset{\stackrel{\mathbf{H}}{\mathbf{|}}}{\mathbf{C}}}\mathbf{-}\stackrel{\stackrel{{\mathbf{C}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{9}}}{\mathbf{|}}}{\underset{\underset{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\mathbf{C}}}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{3\; is}}$$$\begin{gathered} \text{ \\ } \end{gathered}$$
a) 3,4,4 – Trimethylheptane
b) 2 – Ethyl –3, 3– dimethyl heptane
c) 3, 4,4 – Trimethyloctane
d) 2 – Butyl -2 –methyl – 3 – ethyl-butane.
Answer Key:
c) 3, 4,4 – Trimethyloctane
 
9.The IUPAC name of $$H3C-CCH3|CH3|-CH=C(CH3)2
is
a) 2,4,4 – Trimethylpent -2-ene
b) 2,4,4 – Trimethylpent -3-ene
c) 2,2,4 – Trimethylpent -3-ene
d) 2,2,4 – Trimethylpent -2-ene
Answer Key:
a) 2,4,4 – Trimethylpent -2-ene
 
10.The IUPAC name of the compound is $\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{-}\mathbf{C}\mathbf{H}\mathbf{=}\underset{\underset{{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_3}{|}}{\mathrm{C}}-\mathbf{C}{\mathbf{H}}_{\mathbf{2}}\mathbf{-}\mathbf{C}{\mathbf{H}}_{\mathbf{3}}$
a) 3 – Ethyl -2– hexene
b) 3 – Propyl -3– hexene
c) 4 – Ethyl – 4 – hexene
d) 3 – Propyl -2-hexene
Answer Key:
a) 3 – Ethyl -2– hexene
 
11.The IUPAC name of the compound is $\mathbf{C}{\mathbf{H}}_{\mathbf{3}}\mathbf{-}\underset{\underset{\mathbf{O}\mathbf{H}}{\mathbf{|}}}{\mathbf{C}\mathbf{H}}\mathbf{-}\mathbf{C}\mathbf{O}\mathbf{O}\mathbf{H}$
a) 2 – Hydroxypropionic acid
b) 2 – Hydroxy Propanoic acid
c) Propan – 2– ol –1 – oic acid
d) 1 – Carboxyethanol.
Answer Key:
b) 2 – Hydroxy Propanoic acid
 
12.The IUPAC name of is  $\mathbf{C}\mathbf{H}\mathbf{-}\underset{\underset{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\mathbf{|}}}{\mathbf{C}\mathbf{H}}\mathbf{-}\mathbf{C}\mathbf{O}\mathbf{O}\mathbf{H}$
a) 2 – Bromo -3 – methyl butanoic acid
b) 2 - methyl - 3- bromobutanoic acid
c) 3 - Bromo - 2 - methylbutanoic acid
d) 3 - Bromo - 2, 3 - dimethyl propanoic acid.
Answer Key:
c) 3 - Bromo - 2 - methylbutanoic acid
 
13.The structure of isobutyl group in an organ­ic compound is
a) CH₃ – CH₂ – CH₂ – CH₂
b) $\mathbf{C}\mathbf{H}\mathbf{-}\underset{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}{\underset{\mathbf{|}}{\overset{\underset{\mathbf{|}}{\mathbf{C}{\mathbf{H}}_{\mathbf{3}}}}{\mathbf{C}}}}$
c) ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{CH}}-{\mathrm{CH}}_2-$
d) ${\mathrm{CH}}_3-\underset{\underset{ }{|}}{\mathrm{CH}}-{\mathrm{CH}}_2-{\mathrm{CH}}_3$
Answer Key:
c) c) ${\mathrm{CH}}_3-\underset{\underset{{\mathrm{CH}}_3}{|}}{\mathrm{CH}}-{\mathrm{CH}}_2-$
 
14.The number of stereoisomers of 1, 2 – dihydroxycyclopentane
a) 1
b) 2
c) 3
d) 4
Answer Key:
c) 3
 
15.Which of the following is optically active?
a) 3 – Chloropentane
b) 2 Chloro propane
c) Meso – tartaric acid
d) Glucose
Answer Key:
d) Glucose
 
16.The isomer of ethanol is
a) acetaldehyde
b) dimethylether
c) acetone
d) methyl carbinol
Answer Key:
b) dimethylether
 
17.How many cyclic and acyclic isomers are possible for the molecular formula C₃H₆O?
a) 4
b) 5
c) 9
d) 10
Answer Key:
c) 9
 
18.Which one of the following shows functional isomerism?
a) ethylene
b) Propane
c) ethanol
d) CH₂Cl₂
Answer Key:
c) ethanol
 
19. $\stackrel{\overline{)-}}{\mathrm{C}}{\mathrm{H}}_2-\underset{\underset{\mathrm{O}}{\left|\right|}}{\mathrm{C}}-{\mathrm{CH}}_3 \; and {\mathrm{CH}}_2=\underset{\underset{{\mathrm{O}}^{\overline{)-}}}{|}}{\mathrm{C}}-{\mathrm{CH}}_3$  are
a) resonating structure
b) tautomers
c) Optical isomers
d) Conformers.
Answer Key:
b) tautomers
 
20.Nitrogen detection in an organic compound is carried out by Lassaigne’s test.The blue colour formed is due to the formation of.
a) Fe₃[Fe(CN)₆]₂
b) Fe₄[Fe(CN)₆]₃
c) Fe₄[Fe(CN)₆]₂
d) Fe₃ [Fe(CN)₆]₃
Answer Key:
b) Fe₄[Fe(CN)₆]₃
 
21.Lassaigne’s test for the detection of nitrogen fails in
a) H₂N – CO– NH.NH₂.HCl
b) NH₂ – NH₂. HCl
c) C₆H₅ – NH – NH₂. HCl
d) C₆H₅ CONH₂
Answer Key:
c) C₆H₅ – NH – NH₂. HCl
 
22.Connect pair of compounds which give blue colouration / precipitate and white precipi­tate respectively, when their Lassaigne’s test is separately done.
a) NH₂ NH₂ HCl and ClCH₂–CHO
b) NH₂ CS NH₂ and CH₃ – CH2Cl
c) NH₂ CH₂ COOH and NH₂ CONH

d) C₆H₅NH₂ and ClCH₂ – CHO
Answer Key:
d) C₆H₅NH₂ and ClCH₂ – CHO
 
23.Sodium nitropruside reacts with sulphide ion to give a purple colour due to the for­mation of
a) [Fe(CN)⁵ NO]^3-
b) [Fe(NO)⁵ CN]⁺
c) [Fe(CN)⁵NOS]^4-
d) [Fe (CN)⁵ NOS]^3-
Answer Key:
c) [Fe(CN)⁵NOS]^4-
 
24.An organic Compound weighing 0.15g gave on carius estimation, 0.12g of silver bromide. The percentage of bromine in the Compound will be close to
a) 46%
b) 34%
c) 3.4%
d) 4.6%
Answer Key:
b) 34%
  
25.A sample of 0.5g of an organic compound was treated according to Kjeldahl’s method. The ammonia evolved was absorbed in 50mL of 0.5M H₂SO₄. The remaining acid after neutralisation by ammonia consumed 80mL of 0.5 MNaOH, The percentage of nitrogen in the organic compound is.
a) 14%
b) 28%
c) 42%
d) 56%
Answer Key:
b) 28%
 
26.In an organic compound, phosphorus is estimated as
a) Mg₂P₂O₇
b) Mg₃(PO₄)₂
c) H₃PO₄
d) P₂O₅
Answer Key:
a) Mg₂P₂O₇
 
27.Ortho and para-nitro phenol can be separated by
a) azeotropic distillation
b) destructive distillation
c) steam distillation
d) cannot be separated
Answer Key:
c) steam distillation
 
28.The purity of an organic compound is determined by
a) Chromatography
b) Crystallisation
c) melting or boiling point
d) both (a) and (c)
Answer Key:
d) both (a) and (c)
 
29.A liquid which decomposes at its boiling point can be purified by
a) distillation at atmospheric pressure
b) distillation under reduced pressure
c) fractional distillation
d) steam distillation.
Answer Key:
b) distillation under reduced pressure
 
30.Assertion:$\mathbf{C}\mathbf{H}\mathbf{-}\underset{\underset{\mathbf{C}\mathbf{O}\mathbf{O}{\mathbf{C}}_{\mathbf{2}}{\mathbf{H}}_{\mathbf{5}}}{\mathbf{|}}}{\mathbf{C}}\mathbf{=}\mathbf{C}\mathbf{H}\mathbf{-}\mathbf{C}\mathbf{O}\mathbf{O}\mathbf{H}$
 
    3– carbethoxy -2- butenoicacid.
Reason: The principal functional group gets lowest number followed by double bond (or) triple bond.
(a) both the assertion and reason are true and the reason is the correct explanation of assertion.
(b) both assertion and reason are true and the reason is not the correct explanation of assertion.
(c) assertion is true but reason is false
(d) both the assertion and reason are false.
Answer Key:
(a) both the assertion and reason are true and the reason is the correct explanation of assertion.

 

II. Short Answer Questions

11th Chemistry

III. Long Answer Questions

11th Chemistry

IV. Exercise

11th Chemistry