CBSE Class 10 Science Carbon and its compounds Assignment Set D

Very Short answer Type Questions

Question. Write the name and formula of second member of homologous series with general formula C_nH2_n+2
Answer: C₂H₆, Ethane

Question. Write the name and formula of second member of homologous series having general formula C_nH2_n–2.
Answer: C₃H₄, Propyne

Question. Draw electron dot structure of NH₃ molecule. Predict the total no. of bonds around N-atom.
                                                                              OR
A molecule of ammonia has the formula NH₃. Predict the total number of bonds present around nitrogen atom. 
Answer: 

Question. Write the next homologue of each of the following: (i) C₂H₄, (ii) C₄H₆ 
Answer: (i) C₃H₆, (ii) C₅H₈

Question. Write the structure of an alcohol with three carbon atoms in the molecule.
Answer: 

Question. Write the molecular formula of alcohol derived from butane.
Answer: C₄H₉OH or CH₃CH₂CH₂CH₂OH (Butan-1-ol)

Question. Write the molecular formula of an alkyne containing 10 atoms of hydrogen.
Answer: C₆H₁₀

Question. Write the name and molecular formula of the fourth member of alkane series. 
​​​​​​​Answer: C₄H₁₀, Butane (CH₃CH₂CH₂CH₃)

Question. Which of the following organic compounds belong to the same homologous series:
C₂H₆, C₂H₆O, C₂H₆O₂, CH₄O
​​​​​​​Answer: C₂H₆O (C₂H₅OH) and CH₄O (CH₃OH)

Question. The formula of citric acid is shown below:

State the name of —COOH functional group in citric acid.
​​​​​​​Answer: Carboxylic acid

Question. Why covalent compounds are poor conductors of electricity? 
​​​​​​​Answer: It is because covalent compounds do not form ions. 

Question. What would be the electron dot structure of carbon dioxide which has the formula, CO₂?
 ​​​​​​​Answer: 

Question. Which element exhibits the property of catenation to maximum extent and why?
​​​​​​​Answer: Carbon since it forms strong covalent bond, due to smaller atomic size.

Question. Write the molecular formula of first two members of homologous series having functional group Cl.
​​​​​​​Answer: The general formula of the compounds having – Cl functional group is CnH2n + 1Cl. Its two members are:
(i) CH₃Cl (ii) CH₃ – CH₂ – Cl

Question. Write the molecular formula of the 2nd and the 3rd member of the homologous series whose first member is methane (CH₄). 
​​​​​​​Answer: (i) CH₃CH₃ (Ethane); where n is 2
(ii) CH₃CH₂CH₃ (Propane); where n is 3

Question. Write the number of covalent bonds in the molecule of butane (C₄H₁₀). 
​​​​​​​Answer: There are 13 covalent bonds.

Question. State the valency of the carbon atom in (i) an alkane (ii) an alkyne.
​​​​​​​Answer: (i) Four, (ii) Four

Question. Name a cyclic unsaturated carbon compound. 
​​​​​​​Answer: Benzene is cyclic unsaturated carbon compound.

Question. The molecular formula of ‘A’ is C₁₀H₁₈ and ‘B’ is C₁₈H₃₆. Name the homologous series to which they belong. 
​​​​​​​Answer: ‘A’ belongs to Alkynes, ‘B’ belongs to Alkenes.

Question. Write the next homologous of CH₃CH₂OH and HCOOH.
​​​​​​​Answer: CH₃ – CH₂ – CH₂OH. Propanol and, CH₃COOH ethanoic acid

Short answer Type Questions

Question. How many covalent bonds are there in a molecule of ethane, C₂H₆?
​​​​​​​Answer: There are seven covalent bonds in a molecule of ethane:

Question. Name the functional group present in each of the following organic compound:
(i) CH₃COCH₃ (ii) C₂H₅COOH
​​​​​​​Answer: (i) CH₃COCH₃ —- >C=O ketonic group (ii) C₂H₅COOH — (-COOH) Carboxylic acid

Question. Write the name and formula of the 2nd member of homologous series having general Formula CnH₂n.
​​​​​​​Answer: CnH2n: alkene Name: propene(2nd member) formula: C₃H6

Question. Select saturated hydrocarbons from the following:
C₃H₆, C₅H₁₀, C₄H₁₀, C₆H₁₄, C₂H₄
​​​​​​​Answer: Saturated hydrocarbons:
General formula= CnH₂n⁺²
C₄H₁₀, C₆H₁₄

Question. Write the electron dot structure of ethane molecule, C₂H₄​​​​​​​
Answer: 

​​​​​​​

Question. Draw the structure of ethanoic acid molecule, CH₃COOH
​​​​​​​Answer: Structure of ethanoic acid molecule:

Question. Name the functional group present in each of the following organic compounds.
(i) C₂H₅Cl (ii) C₂H₅OH
​​​​​​​Answer: Functional group present in:
(i) C₂H₅Cl – chloro(halide) (ii) C₂H₅OH —- Alcohol

Question. Write the name and structure of an alcohol with three carbon atoms in its molecule.
​​​​​​​Answer: Name of an alcohol: Propanol
Structure of propanol: H₂C – CH₂ – CH₂ – OH

Question. What are isomers? Draw the structure of two isomers of butane C4H10.
​​​​​​​Answer: The organic compounds having the same molecular formula but different structures are known as isomers. Isomers of butane C₄H₁₀.

Question. What are homologous series of carbon compounds? Write the molecular formula of two Consecutive members of homologous series of aldehydes.
​​​​​​​Answer: A series of carbon compounds in which the same functional group substitutes for Hydrogen on a carbon chain is called homologous series. There is difference of –CH₂ in nThe molecular formula of two nearest compounds of a homologous series. Each such Series has same general molecular formula and has a general scientific name. There Is a difference of 14u in the molecular mass of two nearest compound of a series?
Members of homologous series of aldehydes:
H – CHO
CH₃ – CHO
C₂H₅ – CHO

Long answer Type Questions

Question. List two reasons for carbon forming a large number of compounds. Name the type of Bonding found in most of its compounds. Why does carbon form compounds mainly by this kind of bonding?
​​​​​​​Answer: Carbon forms a large number of compounds.
The two properties of carbon which lead to the huge number of carbon compounds are:
-catenation: it’s a unique property of carbon atoms to form bonds with other atoms of Carbon giving rise to large molecules.
-Tetravalency: Since carbon has four valencies, it is capable of bonding with four other atoms Of carbon or atoms of some other monovalent elements.
Carbon compounds are formed mainly by sharing of electron with covalent bond because carbon atoms have 4 electrons in their outermost shell. So, needs to gain or lose Electrons to achieve inert gas electronic configuration. It could gain four electron forming C4-anion. But it is difficult due to energy consideration. It could lose 4 electrons to form C4+cation. But it is difficult due to energy consideration.
Because of this reason carbon Share their electron to form covalent bond only.

Question. What are covalent compounds? Why are they different from ionic compound? List any Three characteristics properties.
​​​​​​​Answer: (i) The chemical bond formed by the sharing of electrons between two atoms is known as a covalent bond. The molecules formed by sharing of electrons between two or more same atoms or between two or more non-metals are called covalent compound.
(ii)Covalent compounds are different from ionic compounds as ionic compounds are Formed by transfer of electrons.
Characteristics of covalent compound:
(i) Covalent compounds usually have low melting and boiling point because force Of attraction between molecules is very weak.
(ii) Covalent compounds are usually insoluble in water but they are soluble in organic compound.
(iii) Covalent compounds do not conduct electricity as they do not contain ions.