Question Set A

CBSE 10th Science Carbon and Its Compounds Sample Question Papers Study Material - QB365

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Questions:

Generic 3

5 x 3 = 15

(i) Define isomerism. Draw all possible isomers of butane.
(ii) "A compound 'X' on combustion gives a yellow flame with lots of smoke." What inference would you draw from this statement?
(iii) State the role of alkaline KMnO₄ in the reaction involving conversion of an alcohol to corresponding carboxylic acid.

The table shows the electronic structures of four elements.

Element	Electronic stucture
P	2, 6
Q	2, 8, 1
R	2, 8, 7
S	2, 8, 8

(i) ldentify which element(s) will form covalent bonds with carbon.
(ii) "Carbon reacts with an element in the above table to form several compounds." Give suitable reason.

How will an organism be benefited if it reproduces through spores?

How does binary fission differ from multiple fission?

What are oxidising agents?

Generic 2

4 x 2 = 8

How can esters be converted into soap?

What are isomers? Draw the structures of two isomers of butane, C₄H₁₀. Why can't we have isomers of first three members of alkane series?

What are the functions performed by the testis in human beings?

What would be the electron dot structure of carbon dioxide which has the formula CO₂ ?

Generic 5

4 x 5 = 20

10.

A carbon compound 'P' on heating with excess cone. H₂SO₄ forms another carbon compound 'Q' which on addition of hydrogen in the presence of nickel catalyst forms a saturated carbon compound 'R'. One molecule of 'R' on combustion forms two molecules of carbon dioxide and three molecules of water. Identify P, Q and Rand write chemical equations for the reactions involved.

11.

Draw a labelled diagram of the longitudinal section of a flower.

12.

An organic compound A on heating with concentrated H₂SO₄ forms a compound B which on addition of one mole of hydrogen in presence of Ni forms a compound C. One mole of compound C on combustion forms two moles of CO₂ and 3 moles of H₂O. Identify the compounds A, B and C and write the chemical equations of the reactions involved.

13.

Draw the structures for the following compounds.
(i) Ethanoic acid
(ii) Bromopentane^*
(iii) Butanone
(iv) Hexanal
Are structural isomers possible for bromopentane?

Multiple Choice Question

6 x 1 = 6

14.

ldentify a group of the unsaturated hydrocarbons from the following

(a)

Propane, ethene, butyne

(b)

Ethene, propane, hexane

(c)

Cyclohexane, methane, ethane

(d)

Butyne, ethene, propyne

15.

According to IUPAC system, the correct name of the organic compound is
\(CH3-\overset { \overset {Br}{ | } }{ CH } -CH2-\overset { \overset { O }{ \parallel } }{ C } -OH\)

(a)

2-bromobutanoic acid

(b)

2-bromobutysis acid

(c)

3-bromobutanoic acid

(d)

3-bromo-2-hydroxybutan-2-one

16.

The upper and lower homologue of C₂H₅OH are respectively

(a)

methyl alcohol and butyl alcohol

(b)

ethyl alcohol and propyl alcohol

(c)

butyl alcohol and propyl alcohol

(d)

propyl alcohol and methyl alcohol

17.

The anther contains

(a)

sepals

(b)

ovules

(c)

carpel

(d)

pollen grains

18.

Asexual reproduction takes place through budding in

(a)

amoeba

(b)

yeast

(c)

plasmodium

(d)

leishmania

19.

Butanone is a four-carbon compound with the functional group

(a)

carboxylic acid

(b)

aldehyde

(c)

ketone

(d)

alcohol

Activity Based Questions

3 x 2 = 6

20.

1. Wet a slice of bread, and keep it in a cool, moist and dark place.
2. Observe the surface of the slice with a magnifying glass.
3. Record your observations for a week.

21.

1) Take two test tubes with about 10 ML of hard water in each.
2) Add five drops of soap solution to one and five drops of detergent solution to the other.
3) Shake both test tubes for the same period.
4) Do both test tubes have the same amount of foam?
5) In which test tube is a curdy solid formed?

22.

1. Make a list of ten things you have used or consumed since the morning.
2. Compile this list with the lists made by your classmates and then sort the items into the adjacent Table.
3. If there are items which are made up of more than one material, put them into both the relevant columns of the table.

Things made of metal	Things made of glass/clay	Others

Case Study Questions

1 x 4 = 4

23.

As neutral atom carbon has electronic configuration K L. To gain inert gas configuration carbon can either 2, 4 donate 4 valence electrons (helium gas configuration) or gain 4 electrons (neon gas configuration), but it cannot do so. To acquire inert gas configuration carbon can only share its 4 valence electrons with other atoms forming covalent bonds. A covalent bond can be defined as a chemical bond formed between two atoms by mutual sharing of valence electrons so that each atom acquires the stable electronic configuration of the nearest noble gas. The concept of covalent bonds was given by Langmuir and Lewis to explain bonding in non-ionic compounds. The covalent bonds are of three types. If each atom contributes one electron, the covalent bond formed is called a single covalent bond and is represented by a single line (-) and if each atom contributes two electrons, the covalent bond formed is called a double bond and is represented by a double line (=) and if each atom contributes three electrons, the covalent bond formed is called a triple bond and is represented by a triple line (=).
(i) Which of the following do not contain a double bond?
I. S02
II. NH3
III. HCl
IV. 02

(a) I and II only

(b) II and III only

(c) III and IV only

(d) I and IV only

(ii) Which of the following contains a triple bond?

(a) N₂

(b) O₂

(c) CO₂

(d) H₂

(iii) The shared pair of electrons is said to constitute a _______________ bond between two hydrogen atoms.

(a) single

(b) double

(c) triple

(d) ionic

(iv) Which of the following molecules has all its atoms joined together by double covalent bonds?

(a) Methane

(b) Water

(c) Carbon dioxide

(d) Nitrogen trichloride

(v) Chlorine forms a diatomic molecule, Cl₂ . The electron dot structure for this molecule is

Assertion and reason

1 x 1 = 1

24.

Assertion: Graphite is a good conductor of electricity.
Reason: It has one free valence electron.
Codes
(a) Both A and R are true, and R is correct explanation of the assertion.
(b) Both A and R are true, but R is not the correct explanation of the assertion.
(c) A is true, but R is false.
(d) A is false, but R is true.

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Answers Key:

Generic 3

5 x 3 = 15

(ii) A compound 'X' is an unsaturated compound, because they do not undergo complete combustion. Therefore, these produces yellow flame with lots of black smoke.
(iii) Alkaline KMnO₄ acts as an oxidising agent in the conversion of an alcohol to corresponding carboxylic acid.
e.g. \(\underset{\text { Alcohol }}{\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{OH}}\) \(\xrightarrow[\text { Alkaline } \mathrm{KMnO}_4]{[\mathrm{O}]}\) \(\underset{\text { Carboxylic acid }}{\mathrm{CH}_3 \mathrm{COOH}}\)

(i) The elements P and R will form covalent bond with carbon because both the elements accept electrons to form ionic as well as covalent bonds.
While element Q (2, 8, 1) donates one electron to form ionic compounds and element 'S' (2, 8, 8) is stable due to complete octet in valence shell. Hence, they do not form covalent bond with carbon.
(ii) Carbon reacts with an element in table to form several compounds because of
(a) Tetravalency of carbon Carbon has electronic structure of (2, 4). Thus, it has four electrons in outermost shell. It is capable of bond formation with four other elements.
(b) Catenation Due to small size, C-C bond is strong. This allow carbon to form long chain compound of different size.

Spores are tiny, spherical, asexual reproductive bodies. They are covered with a hard protective wall. This enables them to survive in unfavourable conditions. They can only germinate and produce new plant under favourable conditions thereby benefitting the organism from dying out.

Differences between binary fission and multiple fission are given below

Binary Fission	Multiple Fission
The parent organism splits to form two new organisms.	The parent organism splits to form many new organisms at the same time.
It takes place during favourable environmental conditions.	It takes place during unfavourable environmental Conditions
It takes place in organisms like Amoeba, Leishmania, etc.	It takes place in organisms like Plasmodium.

Substances that are capable of providing oxygen to other substances are called oxidising agents. Alkaline potassium permanganate (KMnO₄) or acidified potassium dichromate (K₂Cr₂O₇) act as an oxidising agent in oxidising alcohols into acids.

Generic 2

4 x 2 = 8

By saponification reaction, by adding/reacting ester with NaOH

Those compounds, which have same molecular formula but different structural formulae are called isomers.

In first three members of alkane series, branching is not possible. Therefore, we cannot have isomers.

Functions of testes in human beings include:
(i) production of male sex cells-sperms.
(ii) production of male sex hormone-testosterone.

Generic 5

4 x 5 = 20

10.

P = Ethanol / C₂H₅OH
Q = Ethene / CH₂= CH₂
R = Ethane / C₂H₆
C₂H₅OH \(\overset { conc.H_2SO_4 }{ \underset { 443K }{ \longrightarrow } } \) CH₂=CH₂ + H₂O
Ethanol
CH₂=CH₂\(\overset { nickel \ catalyst }{ \underset { H }{ \longrightarrow } } \) CH₃-CH₃
2CH₃-CH₃+7O₂\(\longrightarrow \)4CO₂+6H₂O

11.

12.

i) Since compound C on combustion forms two moles of CO₂ and 3 moles of H₂ O, therefore compound C must contain two carbon atoms and six hydrogen atmos. Thus compound C must be C₂H₆ (ethane)
\(\underset{Ethene(C)}{2C_2H_6}+\underset{Oxygen}{7O_2}\xrightarrow{Heat}\underset{Carbon\ dioxide}{4CO_2}+\underset{Water}{6H_2O}\)
ii) Since compound (C) is obtained by addition of 1 mole of H₂ in presence of Ni to compound (B), therefore (B) must be ethane.
\(\underset{Ethene(B)}{CH2}=CH_2+H_2\xrightarrow{Ni/Heat}\underset{Ethene(C)}{CH_3-CH_3}\)
iii) Since compound (B) is formed by heating compound (A) with cone. H₂SO₄ therefore compound (A) must be ethanol.
\(\underset{Ethanol(A)}{CH_3CH_2OH}\xrightarrow{Conc. H_2SO_4,443K}CH_2=CH_2+\underset{Ethene(B)}{H_2O}\)

13.

There are many structural isomers possible for bromopentane. Among them, the structures of three isomers are given.

Multiple Choice Question

6 x 1 = 6

14.

(d)
Butyne, ethene, propyne

15.

16.

(d)
propyl alcohol and methyl alcohol

17.

(d)
pollen grains

18.

(b)
yeast

19.

Activity Based Questions

3 x 2 = 6

20.

Wet a slice of bread, and keep it in a cool; moist and dark place. Observe the surface of the slice with a magnifying glass. Record your observations for a week.
Observation: On bread grows fungi called bread mould, initially it is white in colour then it becomes brown to black on maturity.

21.

Take two test tubes with 10 ML of hard water in each. Add five drops of soap solution to one and five drops of detergent solution to the other. Shake both the test tubes for the same period.
(i) Solution of hard water and soap forms curdy white precipitate.
(ii) The hard water and detergent forms foam

22.

Things	Metals	Glass/Clay	Other materials
Fan	Aluminium/Iron	_	_
Bed	_	_	Wood (C)
Toothbrush			Plastic, nylon (C)
Spoon	Stainless steel
Tumbler		Glass
Clothes			Cotton (C)
Pencil			Graphite, Wood (C)
Pen	Steel		Plastic (C)
Books			Paper-obtained from wood (C)
Bread			Wheat (C)

a)\(\left.\begin{array}{ll} & \mathrm{CH}_{3} \mathrm{OH} \\ & \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \end{array}\right\} \text { differ by } \mathrm{CH}_{2}\)
Mass of CH₃OH 12 + (1 x 3) + 16 + 1 = 32 u	Mass of C₂H₅OH (12 x 2) + (1 x 5) + 16 + 1 = 46 u Difference ⟶ 46 - 32 = 14 u
b) \(\begin{aligned} &\left.\begin{array}{l} \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH} \\ \mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH} \end{array}\right\} &\text { differ by } \mathrm{CH}_{2} \end{aligned}\)
Mass of C₂H₅OH (12 x 2 ) + (1 x 5) + 16 + 1 = 46 u	Mass of C₃H₇OH (12 x 3) + (1 x 7) + 16 + 1 = 60 u Difference ⟶ 60 - 46 = 14 u
c) \(\left.\begin{array}{l} \mathrm{C}_{3} \mathrm{H}_{7} \mathrm{OH} \\ \mathrm{C}_{4} \mathrm{H}_{9} \mathrm{OH} \end{array}\right\} \quad \text { differ by } \mathrm{CH}_{2}\)
Mass of C₃H₇OH (12 x 3) + (1 x 7) + 16 + 1 = 60 u	Mass of C₄H₉OH (12 x 4) + (1 x 9) + 16 + 1 = 74 u Difference ⟶774 - 60 = 14 u

All 3 groups given above show a similarity⟶Two consecutive members of homologous series differ by CH₂ group and mass 14 u.
CH₃OH, C₂HsOH, C₃H₇OH, C₄H₉OH form a homologous series.

Chloro alkane	Alcohol	Aldehyde	Ketone	Carboxylic acid
CH3Cl	CH3-OH	HCHO

Case Study Questions

1 x 4 = 4

23.

(i) (b): Both NH3 and HCI have single bonds.
(ii) (a): N=N
(iii) (a)
(iv) (c): O=C=O
(v) (c): In chlorine molecule, both chlorine atoms contribute one electron and thus share single electron pair to form single covalent bond. As shared pair is shared by both atoms, they acquire inert gas configuration of argon atom in valence shell.