Carbon and its compound
1.
2.
3.
Soaps are formed by the saponification of
(a) Alcohols (b) simple ester (c) carboxylic acids
(d) glycerides
The functional group of butanone is
(a) Carboxyl (b) ketonic
(c) aldehydic
(d) alcoholic
Enzyme which converts starch into glucose is
(a) Zymase (b) Maltase
(c) Diastase
(d) Invertase
4.
The first compound to be prepared in the laboratory was
(a) Methane (b) Ethyl alcohol (c) acetic acid
(d) Urea.
5.
The IUPAC name of CH 3CHO is
(a) Acetaldehyde (b) Formaldehyde (c) Methyl formaldehyde (d) Ethanal.
H
|
6.
Name the following compounds.
7.
Define soaps?
(a) H − C = O
(b) CH 3 − CH 2 − Cl
8.
Name the second member of alkynes family Give its structure?
9.
Give a chemical test to distinguish between Ethane and ethane.
10.
Complete the following reaction
H 2 SO4
(i) H 2C = CH 2 + H 2O 
→
(ii) HC ≡ CH + Br2 →
(iii) C2 H 5OH + Na →
11.
What is the role of concentrated H 2 SO4 in the esterification reaction?
12.
What will be the formula and electron dot structure of cyclopentane ?
13.
Draw the structures of the following compounds
(a) Ethanoic acid
(b) Bromopentane
(c) Butanone
14.
Define fermentation. Name the enzyme which converts
(a) milk into curd (yogurt)
(b) Cane sugar into glucose and fructose
(c) glucose into ethanol
ANSWERS
Ans1.
Ans6.
(d)
Ans2.
(b)
Ans3.
(a)
Ans4.
(d)
Ans5.
(a) Methanol
(b) Chloroethane
Ans7.
Soaps are the sodium or potassium salts of long chain fatty acids. These are
represented by RCOONa or RCOOR
Ans8.
The second member of the alkyne family is propyne. Its structural formula is
CH 3 − C ≡ CH
Ans9.
Ethene decolorizes the yellow colour of bromine water while ethane does not.
Ans10.
H 2 SO4
→ CH 3 − CH 2 − OH
(i) H 2C = CH 2 + H 2O 
Br
|
Br
|
|
Br
|
Br
(ii) HC ≡ CH + 2 Br2 → H − C − C − H
(iii) 2C2 H 5OH + 2 Na → 2C2 H 5ONa + H 2
Ans11.
In esterification reaction a carboxylic acid reacts with alcohol to form ester and
water in the presence of concentrated sulphuric acid. This reaction is reversible
and this reverse reaction is called ester hydrolysis.
Concentrated sulphuric acid being a strong dehydrating agent removes water
from the reaction mixture. As a result, the reaction proceeds only is the forward
direction to form ester.
conc H 2 So4
RCOOH + ROH 
→ RCOOR + H 2O
Acid
Alcohol
Ester
(d)
Ans12.
It is a cyclic compound with formula C5 H12 . The structure of the compound is
represented as
H
H
C
C
H
H
H
C
C
H
H
H
O
||
H
Ans13.
C
H
H
(a) H − C − C − OH Ethanoic acid
H
(b) CH 3 − CH 2 − CH 2 − CH 2 − CH 2 − Br Bromopentane
O
||
(c) H 3C − C − CH 2 − CH 3 Butanone
Ans14.
The preparation of ethyl alcohol from sugar
( C12 H 22O11 ) is
fermentation.
(a) Lactase converts milk into curd
(b) Invertase converts cane sugar into glucose and fructose
(c) Zymase converts glucose into ethanol.
known as
Carbon and its compound
1.
2.
3.
4.
Rectified spirit is
(a) 50% ethanol
(b) 80% ethanol
(c) 95% ethanol
(d) 40 to 50%
Dilute alkaline KMnO4 solution is
(a) an oxidising agent
(b) a reducing agent
(c) a bleaching agent
(d) none of these
The by product in soap industry is
(a) Isoprene
(b) Ethylene glycol
(c) glycerol
(d) butane
An example of soap is
(a) C15 H 31COONa
(c) C6 H 5COONa
5.
6.
(a) 4
(b) 6
(c) 8
(d) 10
Write the structures of
(ii) Hex anal
Name the following compounds
H
(a) CH 3 − C = 0
8.
(d) C17 H 35OSO3 Na
The number of C-H bonds is ethane C2H6 molecule are
(i) Ethanoic acid
7.
(b) CH 3COONa
(b) CH 3 − CH 2 − OH
Which organic compound is added to make ethanol unfit for drinking purposes? What is the name of the mixture formed?
9.
Write a test to identify the presence of ethanoic acid?
10.
Give names of the following
(a) An aldehyde derived from ethane
(b) Ketone derived from butane
(c) Compound obtained by the oxidation of ethanol by chromic anhydride
11.
What is meant by denatured alcohol? What is the need to denature alcohol?
12.
Write chemical equations of the reactions of ethanoic acid with
(a) Sodium
(b) Sodium carbonate
(c) Ethanol
(d) The presence of conc H2So4
13.
Complete the reaction and names of the products formed
heat
(i) CH 3COOH + NaOH 

→
(ii) C2 H 5OH + O2
alkaline
KMnO4
Conc H 2 SO4
(iii) CH 3COOH + C2 H 5O4 →
14.
(a) Name the gas evolved during fermentation process?
(b) What role is played by yeast in the conversion of cane sugar (C12H22O11) to
ethanol?
(c) How may the following be obtained from pure ethanol? Express chemical
reactions by the chemical equations.
(i) Sodium ethoxide (ii) Ethyl ethanoate (iii) Ethanal
ANSWERS
Ans1.
(c)
Ans5.
(b)
Ans2.
(a)
Ans3.
(c)
Ans4.
(a)
Ans5.
(b)
O
||
Ans6.
(i) CH3- C -on
O
||
(ii) CH3-CH2-CH2-CH2-CH2- C -H
Ans7.
(a) Ethanal
(b) Ethanol
Ans8.
Methanol which is highly poisonous is added to make ethanol unfit for drinking
purpose. The mixture is called methylated spirit or denatured alcohol.
Ans9.
Dip a strip of blue litmus paper in the solution of ethanoic acid. Its colour will
change to red.
Ans10.
(a) Ethanal (CH3CHO)
(b) Butanone (CH3COCH2CH3)
(c) Ethanal (CH3CHO)
Ans11.
Ethyl alcohol which contains small amount of methyl alcohol or copper sulphate is
called denatured alcohol. The purpose of denaturing of alcohol is to make it unfit
for drinking purposes.
Ans12.
(i) 2CH3COOH+2Na → 2CH3COONa+H2
(Sod. Ethanoate)
(ii) 2CH3COOH+Na2CO3 → 2CH3COONa+CO2+H2O
(Sod. Ethanoate)
conc H 2 So4
(iii) CH3COOH+C2H5OH 
→ CH3COOC2H5
(Ethyl ethanoate)
Ans13.
Heat
(i) CH3COOH+NaOH 
→ CH3COONa+H2O
(Sod. Ethanoate)
(ii) C2H5OH+O2
alkaline
CH3COOH+H2
KMnOH
(Ethanoic acid)
Conc. H 2 Sol
(iii) CH3COOH+C2H5OH 
→ CH3COOC2H5+H2O
(Ethylethanoate)
Ans14.
(a) CO2 gas is evolved accompanied by brisk effervescence.
(b) Yeast is the source of enzymes invertase and zymase needed for fermentation.
(c) (i) 2C2H5OH+2Na → 2C2H5ONa+H2
H 2 SO4
(ii) C2H5OH+CH3COOH 
→ CH3COOC2H5+H2O
(Ethyl ethanoate)
CrO3 is
1
(iii) C2H5OH+ O2
CH3CHO+H2O
2
Ch3COOH
Carbon and its compound
1.
An unknown compound has the smell of vinegar. Identify it.
2.
Out of butter and groundnut oil which is unsaturated in nature.
3.
Which has triple bond, C2 H 4 , C3 H 4 , C3 H 6
4.
Which substance is added for the denaturation of ethyl alcohol
5.
Which ions are responsible for making water hard?
6.
Why carbon and its compounds used as fuels in most cases?
7.
A compound X has the molecular formula C3 H 6O with structural formula
CH 3CH 2CHO . Give its IUPAC name. Can another compound have the same
molecular formula? Give the structure and IUPAC name of that compound also.
8.
Why CHO group cannot be present in the middle of the carbon atom chain?
11.
9.
Two carbon atoms cannot be linked to each other by more three covalent bonds. Why?
10.
Write three difference between ethanol and ethanoic acid on the basis of chemical properties?
Given a chemical test to distinguish between
(i) Ethane and ethene (ii) Ethanol and ethanoic acid (iii) Soaps and Detergents
12.
Name the functional groups present in the following compounds?
(i) CH 3 − CH 2 − CH 2 − OH (ii) CH 3 − CH 2 − CH 2 − COOH (iii) CH 3 − CH 2 − CHO
13.
14.
What are esters? Write an equation to show the formation of ester?
(a) Why does carbon form largest number of compounds?
(b) Why are some of these called saturated and other unsaturated compounds?
(c) Which of these two is more reactive?
(d) Write the names of the following compounds
(i) CH 2 − CH 2 − Br
(ii) CH 3 − CH − CH − CH − C ≡ C − H
ANSWERS
Ans1.
Acetic acid
Ans5.
Ca 2+ and Mg 2+
Ans6.
Ans2.
Groundnut oil
Ans3.
C3 H 4
Ans4.
Carbon burns in oxygen or air to form CO2 gas. This reaction is highly
exothermic that is why different form of coals are used as fuels
Ans7.
The IUPAC name of X is propanal.
Another similar compound is Y is.
O
||
CH 3 − C − CH 3 (Propanone)
X and Y are related to each other as functional isomers.
Ans8.
The CHO group is a terminal functional group since three valencies of the Catom are already satisfied, so this group cannot be present in the middle of the
chain.
Ans9.
When two carbon atoms are to linked by four covalent bonds their nuclei come
so close to one another that the force of repulsion between them will push these
apart. As a result, a stable molecule will not be formed.
Ans10. (i)
On adding a small amount of
NaHCO3 to ethanoic acid CO2 gas is evolved
with brisk effervescence and no such reaction takes place in case of ethanol
CH 3COOH + NaHCO3 → CH 3COONa + CO2 + H 2O
(ii)
(iii)
Ethanol is neutral so does not bring any change in the colour of litmus paper
but ethanoic acid is acidic and changes the colour of a blue litmus strip to
red when dipped in it.
Ethanoic acid reacts with NaOH and KOH to form salt and water where as
ethanol fails to react.
CH 3COOH + NaOH → CH 3COONa + H 2O
CH 3COOH + KOH → CH 3COOK + H 2O
Ans11. (i)
(ii)
Ethane decolorizes the yellow colour of bromine while ethane does not.
Ethanoic acid gives a brisk effervescence with sodium hydrogen carbonate
while ethanol does not.
(iii)
Soaps form curdy white precipitate or scum with hard water while
detergents do not form any precipitate.
Methyl Alcohol
Ans12.
(i) −OH ( ol )
(ii) −COOH ( oic acid )
(iii) −CHO ( al )
Ans13.
Esters are pleasant smelling compounds and are commonly used as flavoring
agents. Monocarboxylic acids react with alcohol to form esters and water. This
reaction is called as esterification
conc H 2 SOH
CH 3COOH + CH 3OH 
→ CH 3COOCH 3 + H 2O
Methyl Ethonoate (Ester)
Conc. H 2 SO4
CH 3COOH + C2 H 5OH →
CH 3COOC2 H 5 + H 2O
Ethyl Ethanoate (Ester)
Ans14. (a) Carbon forms large number of compounds called organic compounds due to
the self linking property called catenation.
(b) Compounds which has only C-C (single bond) present are saturated
compounds whose as those compounds which has C=C (double bond) or
C ≡ C (triple) bond is present are called unsaturated compounds.
(c)
Unsaturated compounds are more reactive than saturated compounds
(d) (i) Bromoethane
(ii) Hex-1-yne
Carbon and its compound
1.
The odour of acetic acid resembles that of
(a) Rose
(b) Burning Plastic
(c) Vinegar
(d) Kerosene
2.
Diamond is not a good conductor of electricity because
(a) is very hard
(b) Its structure is very compact
(c) It is not soluble in water
(d) It has no free electrons to conduct electric current.
3.
Alcohols can be produced by the hydration of
(a) Alkenes
(b) alkynes
(c) alkenes
(d) acids
4.
The IUPAC name of CH3CHO is
(a) Acetaldehyde
(b) formaldehyde
(c) methyl formaldehyde
(d) ethanol
5.
IUPAC name of first member of homologous series of ketones is
(a) Ethanone
(b) methanone
(c) Propanone
(d) Butanone
6.
What are the properties of carbon which lead to the huge number of carbon compounds we see around us?
7.
Name the following compound
(a) CH3-CH2-Br
(b) CH3 − CH2 − CH2 − C ≡ CH
8.
9.
Why is conversion of ethanol into ethanoic acid an oxidation reaction?
A mixture of ethyne and oxygen is used for welding. Can you justify why a mixture of ethyne and air is not-used?
10.
11.
What is a homologous series? State any two characteristics of homologous series?
Give the structural formulas for
(i) Methyl Ethanote
(ii) Ethyl ethanoate
Write two uses of Ester?
12.
What are enzymes? Name the enzymes required for the fermentation of sugarcane to ethanol?
13.
The formula of an ester is C3H7COOC2H5 write the formulae of the acid and alcohol from which the ester is prepared.
14.
An organic compound A is widely used as a preservative in pickles and has a
molecular formula C2H4O2. This compound reacts with ethanol to form a sweet
smelling compound B.
(a) Identify the compound A.
(b) Write the chemical equation for its reaction with ethanol to form compound B.
(c)
How can we get compound A back from B.
(d)
Name the process and write the corresponding chemical equation.
(e) Which gas is produced when compound A reacts with washing soda? Write the chemical equation?
ANSWERS
Ans1.
Ans6.
(c)
Ans2.
(d)
Ans3.
(a)
Ans4.
(d)
Ans5.
(c)
(i) Self linking property called catenation
(ii) Carbon is tetravalent and can readily unite with atoms like hydrogen, oxygen
etc by electron sharing
Ans7.
(i) Bromoethane
(ii) Hex-1- yne
Ans8.
Ethanoic acid has one O2, atom more and two hydrogen atoms less then ethanol.
And loss of hydrogen is known as oxidation and gain of oxygen is known as
oxidation. Therefore it is an oxidation reaction.
Ans9.
When ethyne is burnt in oxygen, large quantity of heat and light is produced. The
heat evolved can be used for gas welding which is used for welding broken pieces
of articles. As air contains mixture of nitrogen and oxygen and nitrogen which is
more in amount does not support combustion. Therefore it is always better to use
oxygen for the combustion of ethyne.
Ans10.
A series of similarly constituted compounds in which the members present have
the same functional group, same chemical properties and any two successive
members is a particular series differ in their molecular formula by CH2 group.
(i) Same functional group
(ii) Same chemical properties.
O
||
Ans11.
(i) H − C − OCH 3
(ii) CH 3COOC2 H 5
Uses of esters:
(1) Esters have pleasant smell. These are used as flavouring agents and also
in perfumes.
(2) Esters of glycerol know as triglycerides are used in the manufacture of
soaps. This reaction is called saponification reaction.
Ans12.
Enzymes are the biocatalysts which catalyse the reactions in the living beings. In
the process of fermentation of sugar into ethanol, two enzymes are used.
C12 H 22O11 + H 2O Invertase C6 H12O6 + C6 H12O6
Sugar
glucose
C6 H12O6
Zymase
fructose
2C2 H5OH+2CO2
Glucose and Fructose
Ans13.
The molecular formula for acid is C3H7COOH (Butanoic acid) and for alcohol is
C2H5OH (Ethyl alcohol)
C3 H 7 COOH
+
Butanoic acid
Ans14.
→
C2 H 5OH
C3 H 7COOC2 H 5 + H 2O
Ethyl alcohol
Butanoate (Ester)
(a) Compound A is ethanoic acid (CH3COOH)
(b) CH3COOH
+ C2H5OH → CH3COOC2H5+H2O
Ethanoic acid
Ethyl Ethanoate (Ester)
(c) CH3COOC2H5+H2O H + CH3COOH +C2H5OH
Ethanoic acid
(d) The process is known as ester hydrolysis.
(e) CO2 is produced with effervescence when compound A reacts with washing
soda which is chemically Na2CO3
2CH3COOH+Na2CO3 → 2CH3COONa+H2O+CO2