ICSE
Class 10
Organic
Chemistry
Previous Year
Questions
Q1. Name the following/Give one word or phrase for the following:
(i)
A
gaseous hydrocarbon commonly used for welding purposes. [2011][1]
Show Answer
Ans.
Acetylene
(ii)
A
reaction in which hydrogen of an alkane is replaced by a halogen. [2013][1]
Show Answer
Ans.
Halogenation
(iii)
Hydrocarbons
containing a >C=O functional group.
[2014][1]
Show Answer
Ans.
Ketones
(iv)
Process
by which ethane is obtained from ethene.
[2015][1]
Show Answer
Ans.
Hydrogenation
(v)
A
hydrocarbon which contributes towards the greenhouse effect. [2015][1]
Show Answer
Ans.
methane
(vi)
Distinctive
reaction that takes place when ethanol is
treated with acetic acid. [2015][1]
Show Answer
Ans.
Esterification
(vii)
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. [2015][1]
Show Answer
Ans.
Catenation
(viii)
Reaction
when an alkyl halide is treated with
alcoholic potassium hydroxide. [2015][1]
Show Answer
Ans.
Dehydrohalogenation
(ix)
The
catalyst used in the conversion of ethyne to
ethane. [2016][1]
Show Answer
Ans.
Nickel
(x)
The
type of reactions alkenes undergo. [2016][1]
Show Answer
Ans.
Addition
reaction
(xi)
Ice
like crystals formed on cooling an organic acid
sufficiently. [2017][1]
Show Answer
Ans.
Glacial
acetic acid
(xii)
Hydrocarbon
containing a triple bond used for welding
purposes. [2017][1]
Show Answer
Ans.
Ethyne
(xiii)
The
property by virtue of which the compound has the
same molecular formula but different structural formulae. [2017][1]
Show Answer
Ans.
Isomerism
(xiv)
The
compound formed where two alkyl groups are linked
by >C=O group. [2017][1]
Show Answer
Ans.
Ketones
(xv)
The
tendency of an element to form chains of identical
atoms. [2018][1]
Show Answer
Ans.
Catenation
(xvi)
The
compound with 3 carbon atoms and functional group
is a carboxyl. [2019][1]
Show Answer
Ans.
Propanoic
acid
(xvii)
The
first homologue whose general formula is CnH2n.
[2019][1]
Show Answer
Ans.
Ethene
(xviii)
The
compound that reacts with acetic acid to form
ethyl ethanoate. [2019][1]
Show Answer
Ans.
Ethanol
(xix)
The
compound formed by complete chlorination of
ethyne. [2019[1]
Show Answer
Ans.
1,1,2,2-tetrachloroethane
(xx)
The
reaction in which carboxylic acid reacts with
alcohol in the presence of conc. H2SO4 to form a
substance having a fruity smell. [2020][1]
Show Answer
Ans.
Esterification
Q2. Write the IUPAC names of each of the following:
2016
Show Answer
Ans.
1.
Prop-1-ene
2. But-2-yne
3. Ethan-1-al
2018
Show Answer
Ans.
1.
Methan-1-al
2. Propan-1-ol
3. But-2-ene
2019
Show Answer
Ans.
1. Prop-1-yne
2. Ethanal
Acetaldehyde
[2020][1]
Show Answer
Ans.
Ethanal
Acetylene
[2020][1]
Show Answer
Ans. Ethyne
Q3. Give reasons as to why:
(i)
almost
90% of all known compounds are organic in nature. [2011][1]
Show Answer
Ans.
It is so
because 90% of all known compounds contain carbon and hydrogen. Carbon forms so
many compounds due to its unique property of catenation and tetravalency.
(ii)
it
is dangerous to burn methane in an insufficient supply of air. [2011][1]
Show Answer
Ans.
Because it
will form carbon monoxide which is poisonous in nature.
(iii)
Methane
does not undergo addition reactions, but
ethene does. [2013][1]
Show Answer
Ans.
Because
methane is a saturated hydrocarbon and does not contain any double bond whereas
ethene is an unsaturated hydrocarbon and contains a double bond.
(iv)
ethyne
is more reactive than ethane. [2013][1]
Show Answer
Ans.
Ethane is a
saturated hydrocarbon whereas ethyne is an unsaturated hydrocarbon and contains
a triple bond which can undergo addition reactions. Hence, ethyne is more
reactive than ethane.
(v)
Hydrocarbons
are excellent fuels. [2013][1]
Show Answer
Ans.
Hydrocarbons are excellent fuels because they ignite easily at low temperature
and liberate a large amount of heat without leaving any residue.
(vi)
Soda
lime is preferred to sodium hydroxide in the
laboratory preparation of methane. [2020][1]
Show Answer
Ans.
Because
sodium hydroxide is deliquescent and absorbs moisture from the atmosphere which affects
the production of methane.
Q4. Choose the correct answer from the options given below:
(i)
The
functional group present in acetic acid is: [2011][1]
a.
Ketonic
group
>C=O
b.
Hydroxyl
group -OH
c.
Aldehyde
---CHO
d.
Carboxyl
---COOH
Show Answer
Ans.
d.
Carboxyl—COOH
(ii)
The
unsaturated hydrocarbons undergo: [2011][1]
a.
a
substitution reaction
b.
an
oxidation reaction
c.
an
addition reaction
d.
none
of the above
Show Answer
Ans.
c. an
addition reaction
(iii)
The
number of C-H bonds in ethane molecule are:
[2011][1]
a.
Four
b.
Six
c.
Eight
d.
Ten
Show Answer
Ans.
b. six
(iv)
Identify
the statement that is incorrect about
alkanes: [2013][1]
a.
They
are hydrocarbons.
b.
There
is a single covalent bond between carbon and
hydrogen.
c.
They
can undergo both substitution as well as addition
reactions.
d.
On
complete combustion, they produce carbon dioxide
and water.
Show Answer
Ans.
c. They can
undergo both substitution as well as addition reactions.
(v)
The
I.U.P.A.C name of acetylene is: [2014][1]
a.
propane
b.
propyne
c.
ethene
d.
ethyne
Show Answer
Ans.
d. ethyne
(vi)
Identify
the statement which does not describe the
property of alkenes: [2015[1]
a.
They
are unsaturated hydrocarbons.
b.
They
decolourise bromine water.
c.
They
can undergo addition as well as substitution
reactions.
d.
They
undergo combustion with oxygen forming carbon
dioxide and water.
Show Answer
Ans.
c. They can
undergo addition as well as substitution reactions.
(vii)
If
the molecular formula of an organic compound is C10H18,
it is: [2017][1]
a.
alkene
b.
alkane
c.
alkyne
d.
not
a hydrocarbon
Show Answer
Ans. c. alkyne
(viii)
The
organic compound which undergoes substitution
reaction is: [2018][1]
a.
C2H2
b.
C2H4
c.
C10H18
d.
C2H6
Show Answer
Ans. d. C2H6
(ix)
The
IUPAC name of dimethyl ether is: [2018][1]
a.
Ethoxy
methane
b.
Methoxy
methane
c.
Methoxy
ethane
d.
Ethoxy
ethane
Show Answer
Ans.
b. Methoxy
methane
(x)
A
hydrocarbon which is a greenhouse gas is: [2019][1]
a.
acetylene
b.
ethylene
c.
ethane
d.
methane
Show Answer
Ans.
d. methane
(xi)
The
organic compound having a triple carbon-carbon
covalent bond, is: [2020][1]
a.
C3H4
b.
C3H6
c.
C3H9
d.
C4H10
Show Answer
Ans.
a. C3H4
Q5. Identify the substance underlined, in each of the following cases:
(i)
An
organic compound containing ----COOH functional group. [2017][1]
Show Answer
Ans.
Carboxylic
acid
(ii)
The
organic compound which when solidified, forms an ice like mass.
[2019][1]
Show Answer
Ans.
Glacial
Acetic acid
Q6. Choose the correct word/phrase from within the brackets to complete the following sentences:
(i)
The
catalyst used for conversion of ethene to ethane is commonly …………..
(nickel/iron/cobalt). [2011][1]
Show Answer
Ans.
Nickel
(ii)
When
acetaldehyde is oxidized with acidified potassium dichromate, it forms ……………… (ester/ethanol/acetic
acid) [2011][1]
Show Answer
Ans.
acetic acid
(iii)
Ethanoic
acid reacts with ethanol in presence of
concentrated H2SO4 , so as to form a compound and water.
The chemical reaction that takes place is called ………… .
(dehydration/hydrogenation/esterification)[2011][1]
Show Answer
Ans.
esterification
(iv)
The
product formed when ethene gas reacts with water
in presence of sulphuric acid is ……………. (ethanol/ethanal/ethanoic acid)
[2011][1]
Show Answer
Ans.
ethanol
(v)
The
compound formed when ethanol reacts with sodium is ………. (sodium ethanoate,
sodium ethoxide, sodium propionate) [2014][1]
Show Answer
Ans.
sodium
ethoxide
(vi)
Conversion
of ethene to ethane is an example of
________. (hydration/hydrogenation). [2016][1]
Show Answer
Ans.
hydrogenation
(vii)
The
compound formed when ethene reacts with hydrogen
is _________. (CH4 , C2H6 , C3H8)
[2017][1]
Show Answer
Ans.
C2H6
(viii)
Conversion
of ethanol to ethene by the action of
concentrated sulphuric acid is an example of …………… .
(dehydration/dehydrogenation/dehydrohalogenation) [2019][1]
Show Answer
Ans.
dehydration
(ix)
Substitution
reactions are characteristic reactions of
……………… (alkynes/alkenes/alkanes) [2019][1]
Show Answer
Ans.
alkanes
Q7. Write balanced chemical equations for the following:
(i)
Monochloro
ethane is hydrolysed with aqueous KOH. [2011][1]
Show Answer
Ans.
C2H5Cl
+ KOH(aq) -----> C2H5OH + KCl
(ii) A mixture of soda lime and sodium acetate is heated. [2011][1]
Show Answer
Ans. CH3COONa + NaOH -----Cao 300°C----> CH4 + Na2CO3
(iii)
Ethanol
under high pressure and low temperature is
treated with acidified potassium dichromate. [2011][1]
Show Answer
Ans. CH3CH2OH +2[O] -----Acidified
K2Cr2O7-------> CH3COOH + H2O
(iv)
Water
is added to calcium carbide. [2011][1]
Show Answer
CaC2
+ 2H20 -------> Ca(OH)2 + C2H2
(v)
Ethanol
reacts with sodium at room temperature. [2011][1]
Show Answer
2C2H5OH + 2Na --------> 2C2H5ONa + H2
(vi)
Preparation
of ethane from sodium propionate.
[2014][1]
Show Answer
C2H5COONa + NaOH -----CaO 300°C-----> C2H6 + Na2CO3
(vii)
Preparation
of ethanol from monochloroethane and aq.
sodium hydroxide. [2014][1]
Show Answer
Ans.
C2H5Cl
+ NaOH (aq.) ---boil-----> C2H5OH + NaCl
(viii)
Preparation
of ethanol from ethyl chloride. [2016][1]
Show Answer
Ans.
C2H5Cl
+ KOH (aq.) -------> C2H5OH + KCl
(ix)
Burning
of ethane in plentiful supply of air.
[2016][1]
Show Answer
Ans.
2C2H6
+ 7O2 --------> 4CO2 + 6H2O
(x)
Action
of water on calcium carbide [2016][1]
Show Answer
Ans. CaC2 + 2H2O -------> Ca(OH)2 + C2H2
(xi)
Heating
of ethanol at 170°C in the presence of conc.
sulphuric acid. [2016][1]
Show Answer
Ans.
C2H5OH
----conc. H2SO4 170°C ------> C2H4 + H2O
(xii)
Preparation
of methane from iodomethane. [2017][1]
Show Answer
Ans.
CH3I
+2[H] ----Zn/Cu alcohol-----> CH4 + HI
OR
CH3I +2[H] ---Zn + dil.HCl-----> CH4 + HI
(xiii)
Preparation
of ethane from sodium propionate. [2017][1]
Show Answer
Ans.
C2H5COONa
+ NaOH ---Cao 300°C---> C2H6 + Na2CO3
(xiv)
Action
of alcoholic KOH on bromoethane. [2017][1]
Show Answer
Ans.
C2H5Br + KOH (alc.) -------> C2H4
+ KBr+ H2O
(xv)
Chlorine
gas is reacted with ethene. [2019][1]
Show Answer
Ans.
C2H4
+ Cl2 ------> C2H4Cl2
(xvi)
Preparation
of ethene from bromoethane [2019][1]
Show Answer
Ans.
C2H5Br
+ KOH (alc.) -------> C2H4 + KBr+ H2O
(xvii)
Preparation
of ethyne using calcium carbide [2019][1]
Show Answer
Ans.
CaC2
+ 2H2O ------> Ca(OH)2 + C2H2
(xviii)
Preparation
of methane from sodium acetate. [2019][1]
Show Answer
Ans.
CH3COONa
+ NaOH ------>
(xix)
Producing
ethane from bromo ethane using Zn/Cu couple
in alcohol. [2020][1]
Show Answer
Ans.
C2H5Br
+ 2[H] ------Zn/Cu alcohol----> C2H6 + HBr
OR
C2H5Br + 2[H] ----Zn + dil. HCl----> C2H6 + HBr
(xx)
Complete
combustion of ethane. [2020][1]
Show Answer
Ans. 2C2H6 + 7O2 -------> 4CO2 + 6H2O
Q8. Give balanced chemical equations for the following conversions: [2015][3]
(i)
Ethanoic
acid to ethyl ethanoate
Show Answer
Ans. C2H5OH + CH3COOH ----conc. H2SO4----> CH3COOC2H5 + H2O
(ii)
Calcium
carbide to ethyne
Show Answer
Ans.
CaC2
+ 2H20 ------> Ca(OH)2 + C2H2
(iii)
Sodium
ethanoate to methane
Show Answer
Ans.
CH3COONa
+ NaOH ------CaO 300°C----> Na2CO3 + CH4
Q9. Give balanced equations for the laboratory preparations of the following organic compounds: [2013][4]
(i)
A
saturated hydrocarbon from iodomethane.
Show Answer
Ans.
CH3I
+2[H] ---Zn/Cu C2H5OH----> CH4 + HI
OR
CH3I +2[H] ----Zn + dil.HCl----> CH4 + HI
(ii)
An
unsaturated hydrocarbon from an alcohol.
Show Answer
Ans.
C2H5OH
-----conc. H2SO4 170°C----> C2H4 + H2O
(iii)
An
unsaturated hydrocarbon from calcium carbide.
Show Answer
Ans.
CaC2
+ 2H2O ------> Ca(OH)2 + C2H2
(iv)
An
alcohol from ethyl bromide.
Show Answer
Ans. C2H5Br +KOH (aq.) ------->C2H5OH + KBr
Q10. Give the structural formula for the following:
(i)
Methanoic
acid [2012]1]
Show Answer
(ii)
Ethanal
[2012][1]
Show Answer
(iii)
Ethyne
[2012][1]
Show Answer
(iv)
Acetone
[2012][1]
Show Answer
(v)
2-methyl
propane [2012][1]
Show Answer
(vi)
An
isomer of n-butane [2013][1]
Show Answer
(vii)
2-propanol
[2013][1]
Show Answer
(viii)
Diethyl
ether
[2013][1]
Show Answer
(ix)
ethanol [2014][1]
Show Answer
(x)
1-propanal [2014][1]
Show Answer
(xi)
ethanoic
acid
[2014][1]
Show Answer
(xii)
1,2-dichloroethane
[2014][1]
Show Answer
(xiii)
2-methyl
propane [2016][1]
Show Answer
(xiv)
Ethanoic
acid [2016][1]
Show Answer
(xv)
Butan-2-ol
[2016][1]
Show Answer
(xvi)
2,
3-dimethyl butane [2017][1]
Show Answer
(xvii)
diethyl
ether [2017][1]
Show Answer
(xviii)
propanoic
acid [2017][1]
Show Answer
(xix)
Two
isomers of butane [2018][2]
Show Answer
(xx)
acetic
acid
[2019][1]
Show Answer
(xxi)
2,2-dimethyl
pentane [2020][1]
Show Answer
(xxii)
Methanol
[2020][1]
Show Answer
(xxiii)
Iso
propane [2020][1]
Show Answer
(xxiv)
isomers
of pentane [2020][3]
Show Answer
**Click on the image to view it clearly if it is not clear.
Q11. 2016[2]
Show Answer
ii. Reddish brown colour of bromine solution decolourises.
Q12. State one observation for each of the following:
(i)
Bromine
vapours are passed into a solution of ethyne in carbon tetrachloride. [2012][1]
Show Answer
Ans.
Brown
colour of bromine vapours decolourises and a colourless solution is obtained.
(ii)
When
the gaseous product obtained by dehydration of ethyl alcohol is passed through
bromine water. [2015][1]
Show Answer
Ans.
Brown colour
of bromine water decolourises.
(iii)
Addition
of ethyl alcohol to acetic acid in the
presence of concentrated sulphuric acid. [2017][1]
Show Answer
Ans.
Fruity
smell of ester
Q13. Some word/words are missing in the following statements. You are required to rewrite the statements in the correct form using the appropriate word/words:
(i)
Ethyl
alcohol is dehydrated by sulphuric acid at a temperature of about 170°C.
[2012][1]
Show Answer
Ans.
Ethyl
alcohol is dehydrated by concentrated sulphuric acid at a temperature of
about 170°C to form ethylene.
Q14. From the following organic compounds given below, choose one compound in each case which relates to the description [i] to [iv]: [2012][4]
[Ethyne,
ethanol, acetic acid, ethene, ethane]
(i)
An
unsaturated hydrocarbon used for welding purposes. [2015]
Show Answer
Ans.
Ethyne
(ii)
An
organic compound whose functional group is carboxyl.
Show Answer
Ans.
acetic acid
(iii)
A
hydrocarbon which on catalytic hydrogenation gives a
saturated hydrocarbon.
Show Answer
Ans.
ethene
(iv)
An
organic compound used as a thermometric liquid.
Show Answer
Ans.
ethanol
(v)
This
gas is also a saturated hydrocarbon. [2015]
Show Answer
Ans.
ethane
Q15.
Why is
pure acetic acid known as glacial acetic acid? [2012][1]
Show Answer
Ans.
Because on
cooling below its melting point or below room temperature, it solidifies and
forms little ice-like crystals.
Q16.
Give a
chemical equation for the reaction between ethyl alcohol and acetic acid.
[2012][1]
Show Answer
Ans. C2H5OH + CH3COOH ---conc. H2SO4--->CH3COOC2H5 + H2O
Q17.
Identify
the gas evolved in the following reactions:
(i)
Sodium
propionate is heated with soda lime. [2013][1]
Show Answer
Ans.
Ethane
(ii)
Reaction
of ethanol and sodium. [2018][1]
Show Answer
Ans.
Hydrogen
(iii)
Ethene
undergoes hydrogenation reaction. [2019][1]
Show Answer
Ans.
Ethane
Q18.
Complete
the following table which relates to the homologous series of hydrocarbons:
[2018][6]
|
General
formula |
IUPAC
name of the homologous series |
Characteristic
bond type |
IUPAC
name of the first member of the series |
|
CnH2n-2
|
(A)
………… |
(B)
……… |
(C)
………….. |
|
CnH2n+2
|
(D)
………… |
(E)
……….. |
(F)
………….. |
Show Answer
Ans.
A. Alkyne
B. Triple covalent bond
C. Ethyne
D. Alkane
E. Single covalent bond
F. Methane
Q19.
A
compound X (having vinegar like smell) when treated with ethanol in the
presence of the acid Z, gives a compound Y which has a fruity smell. The
reaction is: [2018][4]
C2H5OH
+ X -----Z---> Y + H2O
(i)
Identify
Y and Z.
(ii)
Write
the structural formula of X.
(iii)
Name
the above reaction.
Show Answer
Ans.
(i)
Y
is ethyl ethanoate and Z is concentrated sulphuric acid.
ii.
(iii)
Esterification
Q20.
Give a
chemical test to distinguish between the following pair of compounds:
(i)
Ethene
gas and ethane gas[2013][1]
Show Answer
Ans.
On adding
few drops of bromine solution in carbon tetrachloride with the hydrocarbon, the
reddish brown bromine solution decolourises in ethene but no change is observed
with ethane gas.
Q21.
Distinguish
between the following pairs of compounds using the test given within brackets:
(i)
Ethane
and ethene (using alkaline potassium permanganate solution). [2014][1]
Show Answer
Ans.
No change
is observed with ethane but purple colour decolourises with ethene.
Q22.
State
the conditions required for the following reactions to take place:
(i)
Catalytic
hydrogenation of ethyne [2014][1]
Show Answer
Ans.
In the
presence of catalyst like finely divided nickel, platinum, etc. and on heating
to about 300°C.
(ii)
Preparation
of ethyne from ethylene dibromide. [2014][1]
Show Answer
Ans. Hot and concentrated alcoholic solution of potassium hydroxide.
Q23.
Using their
structural formulae, identify the functional group by circling them: [2015][2]
(i)
Dimethyl
ether
Show Answer
Ans.
(ii)
Propanone
Show Answer
Ans.
Click on the image to view it clearly.
Q24.
What
is the special feature of the structure of ethyne? [2019][1]
Show Answer
Ans.
It contains
a carbon-carbon triple covalent bond.
Q25.
Name
the saturated hydrocarbon containing two carbon atoms. [2019][1]
Show Answer
Ans.
Ethane
Q26. Arrange the following according to the instructions given in brackets: [2019][1]
Ethane, methane, ethene, ethyne. (In the increasing order of the molecular weight) [H=1, C=12]
Show Answer
Ans. methane, ethyne, ethene, ethane
Q27. Copy and complete the following paragraph using the options given in the brackets: [2020][4]
Alkenes are a homologous series of (i) ……….. (saturated/unsaturated) hydrocarbons characterized by the general formula (ii) …………. (CnH2n+2/CnH2n). Alkenes undergo (iii) …………. (addition/substitution) reactions and also undergo (iv) ………… (hydrogenation/dehydrogenation) to form alkanes.
Show Answer
Ans.
(i) unsaturated
(ii) CnH2n
(iii) addition
(iv) hydrogenation
Thanks for using our free and high quality study material.
Hope you liked it.
Please write about your experience in comments.
Q 10 part (v1) isomer of n butane I think you have given iso butane
ReplyDelete