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Total Time: 35 min
CHAPTER WISE CLASS TEST
(Test # 4)
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.Which of the following compounds is expected to give addition reaction?
(A) CH3 – CH3(B) CH2 = CH2✔(C) CH4(D) CH3–CH2–CH3
2.Dehydration of ethanol is carried out using:
(A) Dilute H2SO4(B) Concentrated H2SO4✔(C) HCl(D) NaOH
3.Which of the followings is not used as a fuel?
(A) LPG(B) CNG(C) Diesel(D) Asphalt✔
4.Addition of hydrogen to alkenes is called:
(A) Halogenation(B) Hydration(C) Hydrohalogenation(D) Catalytic hydrogenation✔
5.Indicate the type of the following reaction: CH4 + 2O2CO2 + 2H2O
(A) Substitution(B) Oxidation✔(C) Reduction(D) Addition
6.The product of addition of HBr to ethene is:
(A) 1,2-Dibromoethane(B) Bromoethane✔(C) Ethanol(D) Ethane
7.Which species acts as a reducing agent in the reaction between ethene and KMnO4?
(A) H2O(B) CH2 = CH2✔(C) KMnO4(D) NaOH
8.In the acetylene torch, acetylene burns in oxygen to produce:
(A) CO and H2(B) CO2 and H2O✔(C) CO2 and H2(D) CO and H2O
TIME: 25 MinSUBJECTIVEMARKS: 17
(PART – I)
Q.2 Write short answers to following questions.(6×2=12)
i.Give two examples of addition reactions.
Ans: (1) Hydrogenation: CH2=CH2 + H2 →(Ni, 200°C) CH3–CH3(2) Halogenation: CH2=CH2 + Br2 → CH2Br–CH2Br
ii.How do alkenes occur in nature? Give examples.
Ans: Alkenes occur in small amounts in plants and in petroleum products. Examples: ethene is produced by ripening fruits and acts as a plant hormone; carotene (in carrots) and lycopene (in tomatoes) are coloured natural compounds containing double bonds; pinene is present in turpentine oil.
iii.Give the names of the compounds obtained from coal tar and petroleum.
Ans: Coal tar: benzene, toluene, naphthalene, phenol and anthracene. Petroleum: petroleum gas (methane to butane), petrol, kerosene oil, diesel oil, lubricating oil, paraffin wax and bitumen.
iv.What is ethyne and what is its common name?
Ans: Ethyne is the simplest alkyne, an unsaturated hydrocarbon with a carbon–carbon triple bond. Formula: C2H2 (HC ≡ CH). Its common name is acetylene.
v.How ethene is oxidized by cold aqueous solution of potassium permanganate.
Ans: When ethene is shaken with cold dilute aqueous (alkaline) KMnO4 solution, its purple colour disappears and ethylene glycol (ethane-1,2-diol) is formed: CH2=CH2 + [O] + H2O → CH2OH–CH2OH
vi.How is acetylene used in ripening of fruits?
Ans: Calcium carbide reacts with moisture to give acetylene gas: CaC2 + 2H2O → C2H2 + Ca(OH)2Acetylene acts like the natural ripening hormone ethene and ripens the fruits artificially. (Its impurities are harmful, so this practice is prohibited.)
(PART – II)
Note: Attempt the following question.
Q.3: Explain with examples the cracking of alkanes.(5)
Ans: Cracking is the breaking of large alkane molecules into smaller, more useful alkanes and alkenes. It is carried out by heating at high temperature (thermal cracking) or in the presence of a catalyst such as zeolite or silica–alumina (catalytic cracking). Examples: C10H22 → C8H18 + C2H4C2H6 → C2H4 + H2C12H26 → C6H14 + 2C3H6Cracking is used to obtain petrol from heavy fractions and to produce ethene and propene for plastics.
