Chapter 4 Carbon And Its Compounds

Question 1. Carbon exists in the atmosphere in the form of

(a) carbon monoxide only

(b) carbon monoxide in traces and carbon dioxide

(c) carbon dioxide only

(d) coal

Question 2. Which of the following statements are usually correct for carbon compounds? These

(i) are good conductors of electricity

(ii) are poor conductors of electricity

(iii) have strong forces of attraction between their molecules

(iv) do not have strong forces of attraction between their molecules

(a) (i) and (iii)

(b) (ii) and (iii)

(c) (i) and (iv)

(d) (ii) and (iv)

Question 3. A molecule of ammonia (NH$_3$) has

(a) only single bonds

(b) only double bonds

(c) only triple bonds

(d) two double bonds and one single bond

Question 4. Buckminsterfullerene is an allotropic form of

(a) phosphorus

(b) sulphur

(c) carbon

(d) tin

Question 5. Which of the following are correct structural isomers of butane?

(i)

(iii)

(ii)

(iv)

(a) (i) and (iii)

(b) (ii) and (iv)

(c) (i) and (ii)

(d) (iii) and (iv)

Question 6. CH$_3$– CH$_2$– OH $\xrightarrow{\text{Alkaline KMnO}_4 + \text{Heat}}$ CH$_3$ – COOH

In the above given reaction, alkaline KMnO$_4$ acts as

(a) reducing agent

(b) oxidising agent

(c) catalyst

(d) dehydrating agent

Question 7. Oils on treating with hydrogen in the presence of palladium or nickel catalyst form fats. This is an example of

(a) Addition reaction

(b) Substitution reaction

(c) Displacement reaction

(d) Oxidation reaction

Question 8. In which of the following compounds, — OH is the functional group?

(a) Butanone

(b) Butanol

(c) Butanoic acid

(d) Butanal

Question 9. The soap molecule has a

(a) hydrophilic head and a hydrophobic tail

(b) hydrophobic head and a hydrophilic tail

(c) hydrophobic head and a hydrophobic tail

(d) hydrophilic head and a hydrophilic tail

Question 10. Which of the following is the correct representation of electron dot structure of nitrogen?

(a)

(b)

(c)

(d)

Question 11. Structural formula of ethyne is

(a) H – C$\equiv$ C – H

(b) $3$ H – C$\equiv$ C –H

(c)

(d)

Question 12. Identify the unsaturated compounds from the following

(i) Propane

(ii) Propene

(iii) Propyne

(iv) Chloropropane

(a) (i) and (ii)

(b) (ii) and (iv)

(c) (iii) and (iv)

(d) (ii) and (iii)

Question 13. Chlorine reacts with saturated hydrocarbons at room temperature in the

(a) absence of sunlight

(b) presence of sunlight

(c) presence of water

(d) presence of hydrochloric acid

Question 14. In the soap micelles

(a) the ionic end of soap is on the surface of the cluster while the carbon chain is in the interior of the cluster.

(b) ionic end of soap is in the interior of the cluster and the carbon chain is out of the cluster.

(c) both ionic end and carbon chain are in the interior of the cluster

(d) both ionic end and carbon chain are on the exterior of the cluster

Question 15. Pentane has the molecular formula C$_5$ H$_{12}$. It has

(a) 5 covalent bonds

(b) 12 covalent bonds

(c) 16 covalent bonds

(d) 17 covalent bonds

Question 16. Structural formula of benzene is

(a)

(b)

(c)

(d)

Question 17. Ethanol reacts with sodium and forms two products. These are

(a) sodium ethanoate and hydrogen

(b) sodium ethanoate and oxygen

(c) sodium ethoxide and hydrogen

(d) sodium ethoxide and oxygen

Question 18. The correct structural formula of butanoic acid is

(a)

(b)

(c)

(d)

Question 19. Vinegar is a solution of

(a) 50% – 60% acetic acid in alcohol

(b) 5% – 8% acetic acid in alcohol

(c) 5% – 8% acetic acid in water

(d) 50% – 60% acetic acid in water

Question 20. Mineral acids are stronger acids than carboxylic acids because

(i) mineral acids are completely ionised

(ii) carboxylic acids are completely ionised

(iii) mineral acids are partially ionised

(iv) carboxylic acids are partially ionised

(a) (i) and (iv)

(b) (ii) and (iii)

(c) (i) and (ii)

(d) (iii) and (iv)

Question 21. Carbon forms four covalent bonds by sharing its four valence electrons with four univalent atoms, e.g. hydrogen. After the formation of four bonds, carbon attains the electronic configuration of

(a) helium

(b) neon

(c) argon

(d) krypton

Question 22. The correct electron dot structure of a water molecule is

(a)

(b)

(c)

(d)

Question 23. Which of the following is not a straight chain hydrocarbon?

(a)

(b)

(c)

(d)

Question 24. Which among the following are unsaturated hydrocarbons?

(i) H$_3$C — CH$_2$ — CH$_2$ — CH$_3$

(ii)

(iii)

(iv)

(a) (i) and (iii)

(b) (ii) and (iii)

(c) (ii) and (iv)

(d) (iii) and (iv)

Question 25. Which of the following does not belong to the same homologous series?

(a) CH$_4$

(b) C$_2$ H$_6$

(c) C$_3$ H$_8$

(d) C$_4$ H$_8$

Question 26. The name of the compound CH$_3$ — CH$_2$ — CHO is

(a) Propanal

(b) Propanone

(c) Ethanol

(d) Ethanal

Question 27. The heteroatoms present in CH$_3$ — CH$_2$ — O — CH$_2$— CH$_2$ Cl are

(i) oxygen

(ii) carbon

(iii) hydrogen

(iv) chlorine

(a) (i) and (ii)

(b) (ii) and (iii)

(c) (iii) and (iv)

(d) (i) and (iv)

Question 28. Which of the following represents saponification reaction?

(a) CH$_3$COONa + NaOH $\rightarrow$ CH$_4$ + Na$_2$CO$_3$

(b) CH$_3$COOH + C$_2$H$_5$OH $\rightarrow$ CH$_3$ COOC$_2$H$_5$ +H$_2$O

(c) 2CH$_3$COOH + 2Na $\rightarrow$ 2CH$_3$ COONa + H$_2$

(d) CH$_3$COOC$_2$H$_5$ + NaOH $\rightarrow$ CH$_3$ COONa + C$_2$ H$_5$OH

Question 29. The first member of alkyne homologous series is

(a) ethyne

(b) ethene

(c) propyne

(d) methane

Question 30. Draw the electron dot structure of ethyne and also draw its structural formula

Question 31. Write the names of the following compounds

(a)

(b)

(c)

(d)

Question 32. Identify and name the functional groups present in the following compounds.

(a)

(b)

(c)

(d)

Question 33. A compound X is formed by the reaction of a carboxylic acid C$_2$H$_4$O$_2$ and an alcohol in presence of a few drops of H$_2$SO$_4$. The alcohol on oxidation with alkaline KMnO$_4$ followed by acidification gives the same carboxylic acid as used in this reaction. Give the names and structures of (a) carboxylic acid, (b) alcohol and (c) the compound X. Also write the reaction.

Question 34. Why detergents are better cleansing agents than soaps? Explain.

Question 35. Name the functional groups present in the following compounds

(a) CH$_3$ CO CH$_2$ CH$_2$ CH$_2$ CH$_3$

(b) CH$_3$ CH$_2$ CH$_2$ COOH

(c) CH$_3$ CH$_2$ CH$_2$ CH$_2$ CHO

(d) CH$_3$ CH$_2$ OH

Question 36. How is ethene prepared from ethanol? Give the reaction involved in it.

Question 37. Intake of small quantity of methanol can be lethal. Comment.

Question 38. A gas is evolved when ethanol reacts with sodium. Name the gas evolved and also write the balanced chemical equation of the reaction involved.

Question 39. Ethene is formed when ethanol at 443 K is heated with excess of concentrated sulphuric acid. What is the role of sulphuric acid in this reaction? Write the balanced chemical equation of this reaction.

Question 40. Carbon, Group (14) element in the Periodic Table, is known to form compounds with many elements.

Write an example of a compound formed with

(a) chlorine (Group 17 of Periodic Table)

(b) oxgyen (Group 16 of Periodic Table)

Question 41. In electron dot structure, the valence shell electrons are represented by crosses or dots.

(a) The atomic number of chlorine is 17. Write its electronic configuration

(b) Draw the electron dot structure of chlorine molecule.

Question 42. Catenation is the ability of an atom to form bonds with other atoms of the same element. It is exhibited by both carbon and silicon. Compare the ability of catenation of the two elements. Give reasons.

Question 43. Unsaturated hydrocarbons contain multiple bonds between the two C-atoms and show addition reactions. Give the test to distinguish ethane from ethene.

Question 44. Match the reactions given in Column (A) with the names given in column (B).

Question 45. Write the structural formulae of all the isomers of hexane.

Question 46. What is the role of metal or reagents written on arrows in the given chemical reactions?

(a)

(b) CH$_3$ COOH + CH$_3$ CH$_2$ OH $\rightarrow$ CH$_3$ COOC$_2$ H$_5$ + H$_2$O

(c) CH$_3$ CH$_2$ OH $\rightarrow$ CH$_3$ COOH

Question 47. A salt X is formed and a gas is evolved when ethanoic acid reacts with sodium hydrogencarbonate. Name the salt X and the gas evolved. Describe an activity and draw the diagram of the apparatus to prove that the evolved gas is the one which you have named. Also, write chemical equation of the reaction involved.

Question 48. (a) What are hydrocarbons? Give examples.

(b) Give the structural differences between saturated and unsaturated hydrocarbons with two examples each.

(c) What is a functional group? Give examples of four different functional groups.

Question 49. Name the reaction which is commonly used in the conversion of vegetable oils to fats. Explain the reaction involved in detail.

Question 50. (a) Write the formula and draw electron dot structure of carbon tetrachloride.

(b) What is saponification? Write the reaction involved in this process.

Question 51. Esters are sweet-smelling substances and are used in making perfumes. Suggest some activity and the reaction involved for the preparation of an ester with well labeled diagram.

Question 52. A compound C (molecular formula, C$_2$H$_4$O$_2$) reacts with Na - metal to form a compound R and evolves a gas which burns with a pop sound. Compound C on treatment with an alcohol A in presence of an acid forms a sweet smelling compound S (molecular formula, C$_3$H$_6$O$_2$). On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A.

Identify C, R, A, S and write down the reactions involved.

Question 53. Look at Figure 4.1 and answer the following questions

(a) What change would you observe in the calcium hydroxide solution taken in tube B?

(b) Write the reaction involved in test tubes A and B respectively.

(c) If ethanol is given instead of ethanoic acid, would you expect the same change?

(d) How can a solution of lime water be prepared in the laboratory?

Question 54. How would you bring about the following conversions? Name the process and write the reaction involved.

(a) ethanol to ethene.

(b) propanol to propanoic acid.

Write the reactions.

Question 55. Draw the possible isomers of the compound with molecular formula C$_3$H$_6$O and also give their electron dot structures.

Question 56. Explain the given reactions with the examples

(a) Hydrogenation reaction

(b) Oxidation reaction

(c) Substitution reaction

(d) Saponification reaction

(e) Combustion reaction

Question 57. An organic compound A on heating with concentrated H$_2$SO$_4$ 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 CO$_2$ and 3 moles of H$_2$O. Identify the compounds A, B and C and write the chemical equations of the reactions involved.