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Class 10 Chemistry Chapter 22 Hydrocarbons Test 5 PDF | Punjab Board 2027 Model Papers
Grade 10 Chemistry Chapter 22 Hydrocarbons Test 5
Prepare for your Class 10 Chemistry Chapter 22: Hydrocarbons Class Test 5 with our chapter-wise test series for the Punjab Board 2027 Model Papers. This test covers Topics 22.1 to 22.3 from the prescribed Chemistry textbook, following the new syllabus issued by PECTAA Punjab. These Class 10 Chemistry chapter-wise tests are designed to help students revise important concepts, assess their preparation, and practise for upcoming board examinations. Use this free educational resource to strengthen your understanding of Hydrocarbons and prepare effectively for the Punjab Boards examinations.
Chapter Wise Class TestTest No. 5Chapter-22Hydrocarbons
1.1 Choose the correct Answer.(Time: 7 Minutes)(Total Marks: 8)
1.Alkene contain carbon-carbon bond is:
(a) single(b) double✔(c) Triple(d) All
2.General formula of alkene is:
(a) CnH2n+1(b) CnH2n✔(c) CnH2n−1(d) CnH2n−2
3.Catalyst used for the cracking of Kerosene oil is:
(a) Ni(b) alcoholic KOH(c) Zeolite✔(d) H2SO4
4.Alkenes gives undergo reaction
(a) Elimination(b) Substitution(c) Addition✔(d) All
5.Which one of following is Non-polar solvent?
(a) CH2 = CH2(b) CCl4✔(c) H2O(d) KOH
6.Formula of steam is
(a) H2SO4(b) H2O✔(c) HBr(d) KMnO4
7.General formula of alkyne is:
(a) CnH2n+2(b) CnH2n−2✔(c) CnH2n(d) CnH2n+1
8.The simplest alkyne is:
(a) Ethane(b) Ethene(c) Acetylene✔(d) Propyne
786Times Educational Project of Pakistan by Muhammad Amjad | Page 1 / 2
Chapter Wise Class TestTest No. 5Chapter-22Hydrocarbons
Total Marks: 17(Subjective Type)Time: 33 Minutes
2.Write short answers to any six (6) questions.[6 × 2 = 12]
(i)Define alkene. Give its general formula and example.
Ans: Alkenes are unsaturated hydrocarbons containing a carbon–carbon double bond (C=C). General formula: CnH2n. Example: ethene, CH2=CH2 (C2H4).
(ii)Give some uses of alkenes.
Ans: (1) Used to make polythene and other plastics. (2) Used to prepare ethanol and ethylene glycol (antifreeze). (3) Ethene is used for artificial ripening of fruits. (4) Used as a raw material for many organic chemicals.
(iii)Define elimination reaction. Give example.
Ans: A reaction in which a small molecule (such as H2O or HX) is removed from a saturated compound to form an unsaturated compound is called an elimination reaction. Example: C2H5OH →(conc. H2SO4, 180°C) CH2=CH2 + H2O
(iv)Write the function of Ethylene.
Ans: Ethylene (ethene) acts as a natural plant hormone that ripens fruits. It is also the raw material for making polythene and ethanol.
(v)Define addition reaction? Give an example.
Ans: A reaction in which atoms or groups add across the double (or triple) bond of an unsaturated compound, forming a saturated compound, is called an addition reaction. Example: CH2=CH2 + H2 →(Ni, 200°C) CH3–CH3
(vi)Give a test to identified saturated and unsaturated hydrocarbon.
Ans: Bromine water test: an unsaturated hydrocarbon decolourises reddish-brown bromine water, but a saturated hydrocarbon does not. (Pink KMnO4 solution is also decolourised by unsaturated hydrocarbons.)
(vii)Write the oxidation process of alkene with KMnO4.
Ans: When ethene is shaken with cold dilute alkaline KMnO4 solution, the purple colour disappears and ethylene glycol is formed: CH2=CH2 + [O] + H2O → CH2OH–CH2OH
(viii)Why acetylene used for welding and cutting purposes?
Ans: Acetylene burns in pure oxygen with a very hot flame (about 3000°C): 2C2H2 + 5O2 → 4CO2 + 2H2O + heatThis oxyacetylene flame can melt and cut metals, so it is used for welding and cutting.
(ix)Why use of calcium carbide is prohibited in our country?
Ans: Calcium carbide is used to ripen fruits artificially. It gives acetylene containing traces of arsenic and phosphorus compounds, which are harmful to health, so its use is prohibited.
Note: Attempt any one question.[5 × 1 = 5]
3.Describe two methods of preparation of ethene.
Ans: (a) Dehydration of ethanol: ethanol is heated with conc. H2SO4 at about 180°C. C2H5OH →(conc. H2SO4, 180°C) CH2=CH2 + H2O(b) Dehydrohalogenation of ethyl halide: ethyl chloride is heated with alcoholic KOH. CH3CH2Cl + KOH(alc.) → CH2=CH2 + KCl + H2O
4.What is alkynes? Why it is important?
Ans: Alkynes are unsaturated hydrocarbons containing a carbon–carbon triple bond (C≡C), with the general formula CnH2n−2. The simplest alkyne is ethyne (acetylene), HC≡CH. Importance: acetylene is used for oxyacetylene welding and cutting of metals and as a raw material for plastics (e.g. PVC), synthetic rubber and many organic chemicals.
786Times Educational Project of Pakistan by Muhammad Amjad | Page 2 / 2
