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Class 10 Chemistry Chapter 22 Hydrocarbons Class Test 2 PDF | Punjab Board 2027 Model Papers
Grade 10 chemistry Chapter 22 Hydrocarbons Test 2
Prepare effectively for your Class 10 Chemistry Chapter 22: Hydrocarbons Class Test 2 with our Punjab Board 2027 Model Papers test series. Designed according to the new syllabus issued by PECTAA Punjab, this chapter-wise test helps students revise important concepts, practise exam-style questions, and assess their preparation for the Class 10 Chemistry examination. Students can use this test as part of their Class 10 Chemistry chapter-wise test series, full unit test preparation, and Punjab Board 2027 exam practice.
CHEMISTRYCHAPTER-22 (OBJECTIVE)CLASS TEST-2
TIME: 10 MINTOTAL MARKS:30MARKS: 8
1. Dehydrohalogenation means removal of:(Q-3)
(a) HX✔(b) H2O(c) H2(d) KCl
2. Catalyst used for the cracking of kerosene oil is:(Q-5)
(a) Ni(b) alcoholic KOH(c) Zeolite✔(d) H2SO4
3. Which one of following is non polar solvent?(Q-8)
(a) CH2 = CH2(b) CCl4✔(c) H2O(d) KOH
4. General formula of alkyne is(Q-12)
(a) CnH2n+2(b) CnH2n−2✔(c) CnH2n(d) CnH2n+1
5. When Petroleum is boiled up to 400°C at least compounds can be obtained:(Q-20)
(a) 300(b) 400(c) 450(d) 500✔
6. Aromatic hydrocarbon, benzene may be produced from:(Q-21)
(a) n-Hexane✔(b) Propane(c) natural gas(d) Fuels
7. Range of carbon atoms in Diesel oil is:(Q-25)
(a) 6–10(b) 10–14(c) 14–16(d) 14–19✔
8. Each Petroleum fraction mainly contains a mixture of:(Q-27)
(a) Acid(b) Hydrocarbon✔(c) Salts(d) Alcohol
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CHEMISTRYCHAPTER-22 (SUBJECTIVE)CLASS TEST-2
TIME: 22 MINMARKS: 22
Attempt any 7 Questions.7×2=14
i.Which methods used for the preparation of alkene?(Q-2)
Ans: Alkenes are prepared by: (1) dehydration of alcohols (ethanol + conc. H2SO4 at 180°C), (2) dehydrohalogenation of alkyl halides (with alcoholic KOH), and (3) cracking of alkanes (industrial method).
ii.How alkene can prepare from alcohol?(Q-4)
Ans: By dehydration (removal of water) of alcohol. Ethanol is heated with conc. H2SO4 at about 180°C: C2H5OH →(conc. H2SO4, 180°C) CH2 = CH2 + H2O
iii.Write application of cracking.(Q-7)
Ans: (1) Cracking converts heavy, less useful fractions of petroleum into petrol (gasoline) and other light fuels. (2) It gives alkenes such as ethene and propene, which are raw materials for plastics and many chemicals. (3) It also produces hydrogen gas.
iv.Write the addition reaction of halogen with alkene.(Q-10)
Ans: Halogens add to the double bond of an alkene (in CCl4 solvent), forming a dihalo-alkane. Example: CH2 = CH2 + Br2 → CH2Br – CH2Br (1,2-dibromoethane). The reddish-brown colour of bromine disappears.
v.Write the oxidation process of alkene with KMnO4(Q-12)
Ans: When ethene is shaken with dilute alkaline (cold) KMnO4 solution, the purple colour disappears and ethylene glycol (ethane-1,2-diol) is formed: CH2 = CH2 + [O] + H2O → CH2OH – CH2OH
vi.How acetylene gas ripen the fruits?(Q-17)
Ans: Calcium carbide reacts with moisture to give acetylene (ethyne) gas: CaC2 + 2H2O → C2H2 + Ca(OH)2 Acetylene acts like the natural ripening hormone (ethene) and speeds up the ripening of fruits.
vii.Write the sources of organic compound.(Q-19)
Ans: The major sources of organic compounds are plants and animals, coal, petroleum and natural gas.
viii.How petroleum is extracted?(Q-21)
Ans: A well is drilled down to the petroleum layer. At first the pressure of natural gas pushes the petroleum up to the surface. When the gas pressure falls and the flow stops, petroleum is taken out with the help of pumps.
ix.Define Petroleum:(Q-23)
Ans: Petroleum (rock oil) is a dark brown or black, viscous liquid found under the earth, which is a complex mixture of hydrocarbons (with small amounts of other compounds). It is the main source of fuels.
x.Which properties depend upon the physical properties of petroleum fraction?(Q-28)
Ans: The uses of petroleum fractions depend upon their physical properties such as boiling point range, viscosity, colour, volatility and ease of ignition.
SECTION-II (4+4)
1.Describe the fractional distillation of petroleum.(Ex. D. 22.2)
Ans: Crude petroleum is first freed from water and salts, then heated in a furnace to about 400°C. The hot vapours enter a tall fractionating tower, which is hotter at the bottom and cooler at the top. Fractions with different boiling ranges condense at different heights and are collected: refinery gas (C1–C4) at the top, then petrol (C5–C10), kerosene (C10–C14), diesel oil (C14–C19), fuel oil, lubricating oil and wax, with bitumen as the residue at the bottom.
2.Explain with examples the cracking of alkanes.(Ex. D. 22.4)
Ans: Cracking is the breaking of large alkane molecules into smaller alkanes and alkenes by heat (thermal cracking) or with a catalyst such as zeolite (catalytic cracking). Examples: C10H22 → C8H18 + C2H4C2H6 → C2H4 + H2
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