Frequently Tested Topics:
Esterification Reaction - equation, reactants, observations
Differentiate between ethene and ethane
Isomerism - definition, structures
Why pure acetic acid is called glacial acetic acid
Types of reactions undergone by alkanes, alkenes, alkynes
General formulae of alkanes, alkenes, alkynes
*Note that other aspects of the chapter are equally important.
Important Past Questions:
Choose the correct answer:
i) The formation of 1, 2 dibromoethane from ethene and bromine is an example of:
A] Substitution B] Dehydration C] Dehydrohalogenation D] Addition
ii) Which of the following statements is wrong about alkanes?
A] They are all saturated hydrocarbons
B] they can undergo addition as well as substitution reactions
C] They are almost non-polar in nature
D] On complete combustion they give out CO2 and water
iii) The organic compound which when mixed with ethyl alcohol makes it spurious:
A] Methanol B] Methanoic acid C] Methanal D] Ethanoic acid
iv) The functional group present in acetic acid is:
A] Ketonic C=O B] Hydroxyl - OH C] Aldehydic - CHO D] Carboxyl - COOH
v) Unsaturated hydrocarbons undergo:
A] Substitution reaction B] Oxidation reaction C] Addition reaction D] None of the above
vi) The number of C-H bonds in ethane molecule are:
A] four B] six C] eight D] ten
vii) Which of the following statements does not describe the property of alkenes:
A] they are unsaturated carbons
B] they decolorise bromine water
C] they can undergo addition as well as substitution reactions
D] they undergo combustion with oxygen forming carbon dioxide and water
viii) If the molecular formula of an organic compound is C10H18, it is:
A] Alkene B] Alkane C] Alkyne D] not a hydrocarbon
ix) The organic compound which undergoes substitution reaction is:
A] C2H2 B] C2H4 C] C10H18 D] C2H6
x) The catalyst used for the conversion of ethene and ethane is commonly:
xi) The chemical reaction in which ethanoic acid reacts with ethanol in the presence of conc. H2SO4 so as to form a compound and water is called:
xii) The IUPAC name of acetylene is:
A] propane B] propyne C] ethene D] ethyne
Give balanced chemical equations for:
i) Calcium carbide and water
(2008, 2011, 2013, 2015, 2016)
ii) Bromoethane and an aqueous solution of sodium hydroxide
iii) Acetic acid is warmed with ethanol in the presence of conc. H2SO4.
(2009, 2012, 2015, 2016)
iv) Laboratory preparation of methane from sodium acetate.
(2009, 2011, 2015)
v) Reaction of one mole of ethene and one mole of chlorine gas.
vi) Action of alcoholic KOH on bromoethane.
vii) Reaction between 1, 2 dibromoethane and alcoholic potassium hydroxide.
viii) Monochloroethane is hydrolysed with aqueous KOH/NaOH.
(2011, 2014, 2016)
ix) Ethanol reacts with sodium at room temperature.
x) Preparation of a saturated hydrocarbon from iodomethane.
xi) An unsaturated hydrocarbon from an alcohol.
xii) Ethane from sodium propionate.
xiii) Burning of ethane in plentiful supply of air.
Name the following:
i) A gaseous hydrocarbon commonly used for welding purposes.
ii) The process by which ethane is obtained from ethene.
iii) A hydrocarbon which contributes towards the greenhouse effect.
iv) The distinctive reaction that takes place when ethanol is treated with acetic acid.
v) The property of elements by virtue of which atoms of the element can link to each other in the form of a long chain or ring structure.
vi) The reaction when an alkyl halide is treated with alcoholic potassium hydroxide.
vii) The gas produced during the reaction of ethanol and sodium.
Identify the following:
i) Reddish brown liquid 'S' is dissolved in water. When ethyne is passed through it, it turns colourless.
ii) Gas evolved when sodium propionate is heated with soda lime.
iii) A reaction in which hydrogen of an alkane is replaced by a halogen.
iv) The catalyst used in the conversion of ethyne to ethane.
v) The type of reactions alkenes undergo.
vi) An organic compound containing COOH functional group.
vii) Ice like crystals formed on cooling an organic acid sufficiently.
viii) The property of elements by virtue of which they have the same molecular formula but different structural formula.
i) Pure acetic acid is known as glacial acetic acid.
ii) Almost 90% of all known compounds are organic in nature.
iii) Methane does not undergo addition reactions, but ethene does.
iv) Ethyne is more reactive than ethane.
v) Hydrocarbons are excellent fuels.
Fill in the blanks:
i) The general formula for alkane is _______. [CnH2n/CnH2n-2/CnH2n+2]
ii) For alkynes the general formula is ________. [CnH2n/CnH2n-2/CnH2n+2]
iii) Ethanol reacts with sodium to give ________. [sodium ethanoate/sodium ethoxide/sodium propanoate]
iv) Conversion of ethene to ethane is an example of ________. [hydration/hydrogenation]
v) The compound formed when ethene reacts with hydrogen is _______. [CH4/C2H6/C3H8]
State the observations for:
i) Bromine vapours are passed into a soln. of ethyne in carbon tetrachloride.
ii) Addition of ethyl alcohol to acetic acid in the presence of concentrated sulphuric acid.
Give the structural formula for:
i) Ethanoic acid (2010, 2014, 2016)
ii) But-2-yne (2010)
iii) Methanoic acid (2012)
iv) Ethyne (2012)
v) 2-methyl propane (2012, 2016)
vi) Isomers of butane (2013, 2018)
vii) 2-propanol (2013)
viii) Ethanol (2014)
ix) 1-propanol (2014)
x) 1, 2 dichloroethane (2014)
xi) Butan-2-ol (2016)
xii) 2, 3 dimethyl butane (2017)
xiii) Butanoic acid (2017)
Distinguish between ethane and ethene.
(2008, 2013, 2014)
Find the odd one out and explain your choice:
i) C3H8, C5H10, C2H6, CH4
ii) Formic acid, nitric acid, acetic acid, propanoic acid
How are the following conversions carried out:
i) Ethyl chloride to ethyl alcohol
ii) Ethyl chloride to ethene
iii) Ethene to ethyl alcohol
iv) Ethyl alcohol to ethene
Define isomerism. Give the IUPAC name of the isomer C4H10 which has a branched chain.
Compound X is bubbled through bromine dissolved in CCl4 and the product formed is CH2Br-CH2Br.
i) Draw the structural formula of X and state what type of reaction X has undergone.
ii) State your observation for the above reaction.
Rewrite the statement with the missing words:
Ethyl alcohol is dehydrated by sulphuric acid at a temperature of about 170C.
A compound X having vinegar smell when treated with ethanol in the presence of acid Z, gives a compound Y which has fruity smell. The reaction is C2H5OH + X → Y + H2O.
i) Identify Y and Z.
ii) Write the structural formula of X.
iii) Name the above reaction.
DIAGRAM BASED QUESTIONS
Give the IUPAC names of: