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Class 10 Chemistry Chapter 21 Organic Chemistry Test 3
Grade 10 Chemistry chapter 21 Organic Chemistry Test 3
Prepare for the Punjab Board Class 10 Chemistry Examination 2027 with Chapter 21: Organic Chemistry – Class Test No. 3. This full chapter test, including the complete textbook exercise, is designed to help students revise important concepts, practice exam-style questions, and assess their understanding of Organic Chemistry. These Punjab Board 2027 Model Papers follow the new syllabus issued by PECTAA Punjab and are part of our comprehensive Class 10 Chemistry Full Unit Model Papers and Chapter-Wise Test Series. Practice this test to strengthen your preparation, improve your problem-solving skills, and build confidence for the 2027 annual board examinations.
Chapter: 21
Total Time: 35 min
CHAPTER WISE CLASS TEST(Test # 3)
Chemistry
Total Marks: 25
NOTE: Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with Marker or Pen ink. Cutting or filling two or more circles will result in zero mark in that question.
TIME: 10 MinOBJECTIVEMARKS: 8
Q.1:(08)
1.Choose the correct IUPAC name for the compound
(A) But-3-ene(B) But-1-ene(C) But-2-ene(D) Butene
The double bond starts at carbon 1, so the name is But-1-ene.
2.Straight chain (non-branched) compounds contain:
(A) Closed ring of carbon atoms(B) Open chain of carbon atoms in a straight line(C) Benzene ring(D) Branched carbon chain
Straight chain compounds have an open, unbranched chain of carbon atoms.
3.Select a branched chain compound.
(A) CH2 = CH – CH2 – CH3
(B)
(C) CH2 – C = CH – CH3
(D) CH3 – CH = CH – CH2 – CH3
(B) has a CH3 group attached to the main chain, so it is branched.
4.Aromatic compounds contain:
(A) Open chain of carbon atoms(B) Benzene ring(C) Saturated carbon chain(D) Heterocyclic ring
Aromatic compounds contain one or more benzene rings.
5.Which is the displayed formula of ethanol?
(A) C2H5OH
(B) CH3 – CH2 – OH
(C)
(D)
A displayed formula shows every atom and every bond, including the O–H bond, so (D) is correct.
6.The structural formula gives enough information to understand:
(A) Only molecular mass(B) Only boiling point(C) Structure of molecule clearly(D) Only solubility
It shows how the atoms are arranged in the molecule.
7.Identify the aldehydic functional group among the following:
(A)
(B)
(C) – OH
(D)
The aldehyde group is –CHO, i.e. C=O with a hydrogen attached: (D).
8.The general formula for alkynes is:
(A) CnH2n(B) CnH2n + 2(C) CnH2n – 2(D) CnHn
Alkynes: CnH2n−2, e.g. C2H2.
TIME: 25 MinSUBJECTIVEMARKS: 17
(PART – I)
Q.2 Write short answers to following questions.(6×2=12)
i.What is the difference between saturated and unsaturated hydrocarbons?
Saturated: only single C–C bonds (alkanes, CnH2n+2), less reactive.
Unsaturated: contain double or triple bonds (alkenes, alkynes), more reactive.
Unsaturated: contain double or triple bonds (alkenes, alkynes), more reactive.
ii.What is the difference between cyclohexane and benzene?
Cyclohexane (C6H12) is a saturated alicyclic ring with only single bonds. Benzene (C6H6) is an aromatic ring with alternate single and double bonds.
iii.Write down the structural formula of Butan-2-ol.
CH3 – CH(OH) – CH2 – CH3
iv.Write the displayed and condensed formula of but-2-ene.
Condensed: CH3 – CH = CH – CH3
Displayed:
Displayed:
v.Write down the formula of ethyl methanoate.
HCOOC2H5 or HCOOCH2CH3
vi.What is a homologous series?
A series of organic compounds with the same functional group and general formula, in which each member differs from the next by a CH2 unit, e.g. CH4, C2H6, C3H8.
(PART – II)
Note: Attempt the following question.
Q.3: Write down five characteristics of a homologous series.(5)
1) All members have the same functional group and general formula.
2) Each member differs from the next by CH2 (14 amu).
3) They show a gradual change in physical properties (melting point, boiling point, density).
4) They have similar chemical properties.
5) They can be prepared by similar general methods.
2) Each member differs from the next by CH2 (14 amu).
3) They show a gradual change in physical properties (melting point, boiling point, density).
4) They have similar chemical properties.
5) They can be prepared by similar general methods.
