Chapter No.3: Organic Chemistry -Chemistry For Class X (2022 and Onward) - Multiple Choice Questions, Fill in the blanks, Concept Diagram

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Organic Chemistry
MULTIPLE CHOICE QUESTIONS (MCQs)

Tick the correct answer from the following:
1. The branch of chemistry which deals with hydrocarbons and their derivatives is known as:
(a) Organic chemistry ✓
(b) Inorganic chemistry
(c) Biochemistry
(d) Physical chemistry

2. The general formula for alkanes is:
(a) C_nH_2n
(b) C_nH_2n+1
(c) C_nH_2n+2 ✓
(d) C_nH_2n-1

3. Which of the following is an alcohol?
(a) CH₃-CHO
(b) CH₃-CH₂-O-CH₃
(c) CH₃-OH ✓
(d) HCOOH

4. Which of the following is a saturated hydrocarbon?
(a) CH₃-CH=CH₂
(b) CH₃-CH₂-CH₃ ✓
(c) CH₃-C=CH
(d) CH₂=CH-C=CH

5. The prefix ‘hept’ stands for the ____ carbon atoms.
(a) 2
(b) 5
(c) 7 ✓
(d) 9

6. The functional group -COOH is used for:
(a) alkynes
(b) alcohols
(c) phenols
(d) Carboxylic acids ✓

7. Polyethene is:
(a) oil
(b) paper
(c) plastic ✓
(d) wood

8. Acetic acid is obtained from:
(a) banana
(b) dates
(c) garlic
(d) vinegar ✓

9. Alkenes:
(a) show the same general formula as alkynes
(b) have carbon-carbon triple bond
(c) have carbon-carbon double bond ✓
(d) are saturated hydrocarbons

10. CH₃-CH₂- is radical.
(a) Methyl
(b) Ethyl ✓
(c) n-propyl
(d) Isopropyl

11. Vital Force Theory was introduced by:
(a) Wohler
(b) Arrhenius
(c) Lewis
(d) Berzelius ✓

12. In 1828, he converted an inorganic compound ammonium cyanate into urea.
(a) Wohler ✓
(b) Arrhenius
(c) Lewis
(d) Berzelius

13. It is an organic compound excreted in the urine of mammals.
(a) Alcohols
(b) Alkynes
(c) Urea ✓
(d) Ketones

14. It ts the key element in all organic compounds.
(a) Oxygen
(b) Carbon ✓
(c) Nitrogen
(d) Iron

15. In organic compounds after carbon, the most frequently used element is:
(a) Hydrogen ✓
(b) Oxygen
(c) Nitrogen
(d) Sodium

16. Which one of these statements is TRUE?
(a) Organic compounds are insoluble in water
(b) Non-polar organic compounds are soluble in benzene
(c) None of these
(d) Both 'a' & 'b' ✓

17. The rate of reactivity of organic compounds is:
(a) fast
(b) moderate
(c) slow
(d) very slow ✓

18. Organic compounds have ______ different sorts of formulae.
(a) 2
(b) 4 ✓
(c) 5
(d) 6

19. Which one indicates the exact number of atoms in one molecule of an organic compound?
(a) Molecular formula ✓
(b) Structural formula
(c) Condensed formula
(d) Dot and cross formula

20. Molecular formula of butane is:
(a) C₃H₈
(b) C₄H₁₀ ✓
(c) C₅H₁₂
(d) C₆H₁₄

21. It is also known as the electronic formula, which depicts the sharing of electrons between distinct atoms in a single molecule of an organic compound.
(a) Molecular formula
(b) Structural formula
(c) Condensed formula
(d) Dot and cross formula ✓

22. Benzene is a/an:
(a) straight chain compound
(b) branched chain compound
(c) heterocyclic compound
(d) cyclic compound ✓

23. More than ____ organic compound (carbon compounds) exist.
(a) 1 million
(b) 3 million
(c) 5 million
(d) 10 million ✓

24. It is the capacity of atoms to build long chains and huge rings by linking with other similar atoms.
(a) Homologous
(b) Isomerism
(c) Catenation ✓
(d) Saturated

25. If two compounds have the same molecular formula but distinct atom arrangements in their molecules or different structural formulas, they are said to be:
(a) Isomers ✓
(b) Homologous
(c) Saturated
(d) Unsaturated

26. A cause / causes for the abundance of organic molecules is / are:
(a) Catenation
(b) Isomerism
(c) None of these
(d) Both 'a' & 'b' ✓

27. Wood has a carbon content of:
(a) 20%
(b) 40% ✓
(c) 60%
(d) 90%

28. lt is a major and important component of natural gas.
(a) Methane ✓
(b) Ethane
(c) Propane
(d) Butane

29. The fundamental unit of carbohydrates is:
(a) starch
(b} cellulose
(c) glucose ✓
(d) protein

30. It is / They are formed as glucose polymerizes further:
(a) Starch
(b) Cellulose
(c) None of these
(d) Both 'a' & 'b' ✓

31. Pulses and beans are high in:
(a) vitamins
(b) protein ✓
(c) oils
(d) fats

32. The general formula for alkenes is:
(a) C_nH_2n ✓
(b) C_nH_2n+1
(c) C_nH_2n+2
(d) C_nH_2n-1

33. C_nH_2n-1 is general formula of:
(a) alkanes
(b) alkenes
(c) alkynes ✓
(d) alcohols

34. C₆H₁₃ ts radical:
(a) Propyl
(b) Pentyl
(c) Hexyl ✓
(d) Octyl

35. C_nH_2n+1 is the general formula of:
(a) alkanes
(b) alkenes
(c) alkynes
(d) alkyl radicals ✓

36. Removal of terminal H form propane, termed as:
(a) n-propyl ✓
(b) isopropyl
(c) ter-propyl
(d) sec-propyl

37. Removal of central H form butane, termed as:
(a) n-butyl
(b) isobutyl
(c) ter-butyl
(d) sec-butyl ✓

38. It is produced by plants through photosynthesis.
(a) Starch
(b) Cellulose
(c) Glucose ✓
(d) Protein

39. They contain carbon-carbon double and triple bonds.
(a) Unsaturated hydrocarbons ✓
(b) Saturated hydrocarbons
(c) Alkanes
(d) Alkyl radicals

40. They have a less amount of carbon and a high amount of hydrogen.
(a) Unsaturated hydrocarbons
(b) Saturated hydrocarbons ✓
(c) Alkanes
(d) Alkyl radicals

41. Which one is less reactive?
(a) Unsaturated hydrocarbons
(b) Saturated hydrocarbons ✓
(c) None of these
(d) Both 'a' & 'b'

42. They burn with yellow and sooty flame in the air.
(a) Unsaturated hydrocarbons ✓
(b) Saturated hydrocarbons
(c) Alkanes
(d) Alkynes

43. In alcohols the functional group is:
(a) alkyl halide
(b) alkoxyl group
(c) carbonyl group
(d) hydroxyl group ✓

44. The polar hydroxyl group (-OH) in alcohols, for example, improves:
(a) melting point
(b) boiling point
(c) solubility ✓
(d) density

45. General Formula of ethers is:
(a) C_nH_2n-2
(b) C_nH_2n+2O ✓
(c) C_nH_2n+1X
(d) C_nH_2n-1OH

46. Functional group of aldehydes is:
(a) =C=C=
(b) -C=C-
(c) -CH=O ✓
(d) =C=O

47. R-CO-OH This is the functional group of:
(a) carboxylic acids ✓
(6) esters
(c) alcohols
(d) phenols

48. Formula of formaldehyde is as follows:
(a) H₃C-CO-CH₃
(b) H₃C-CO-CH₂CH₃
(c) H₃C-CO-H
(d) H-CO-H ✓

49. H₃C-CO-CH₃, This is the formula of:
(a) acetaldehyde
(b) acetone ✓
(c) acetic acid
(d) formaldehyde

50. Formula of formic acid is:
(a) H₃C-CO-CH₃
(b) H₃C-CO-CH₂-CH₃
(c) H₃C-CH=O
(d) H-CO-OH ✓

51. =C-OH, This is the functional group of:
(a) secondary alcohols
(b) tertiary alcohols ✓
(c) secondary ethers
(d) tertiary ethers

52. The organic compounds containing carbon, hydrogen and nitrogen as functional group are called as:
(a) amines ✓
(b) esters
(c) ethers
(d) ketones

FILL IN THE BLANKS:
1. Vital force theory was introduced by Berzelius in 1815.
2. First time Berzelius used the word organic compound for those compounds which are obtained from animals and plants.
3. According to Vital Force Theory, organic compounds can only be prepared in living tissues by vital force.
4. In 1828 the German Chemist Friedrich Wohler converted an inorganic compound ammonium cyanate into urea.
5. Urea is the first synthesized organic compound.
6. Organic compounds are obtained from living things (animals and plants).
7. Carbon is an essential element in all natural and synthesised organic compounds.
8. Hydrocarbons are composed of hydrogen and carbon atoms.
9. The study of hydrocarbons and their derivatives is modern definition of organic chemistry.
10. Organic compounds have weaker bonding than ionic compounds so they have lower melting and boiling points.
11. There are total of 118 elements that are currently known.
12. Self linking property of carbon is called catenation.
13. Pentane (C₅H₁₂) has three isomers.
14. Saturated hydrocarbons or paraffins are alkanes.
15. The compounds having same molecular formula but different structures are termed as isomers.
16. Due to catenation and isomerization millions of organic compounds are existed in the universe.
17. On the basis of chains organic compounds are divided into main two classes- open chain and closed chain (cyclic) compounds.
18. Saturated hydrocarbons contain carbon-carbon single bonds.
19. Alkanes are saturated hydrocarbons.
20. Unsaturated hydrocarbons contain carbon-carbon double and triple bonds.
21. Alkenes (C=C) and alkynes are (C=C) unsaturated hydrocarbons.
22. Organic compounds are insoluble in water.
23. Organic compounds are soluble in organic solvents like benzene, carbon disulphide, ether, alcohols etc.
24. Organic compounds have slow rate of reactions.
25. On combustion, all organic compounds produce one of the common product carbon dioxide.
26. The members of homologous series have same functional group.
27. Coal is also called black gold.
28. In Pakistan the name sui gas is used for natural gas.
29. The name of organic compound is composed of two parts: Prefix + suffix.
30. Prefix tells the number of carbon atoms and suffix tells functional group in each molecule.
31. Alkyl radicals are formed by the removal of hydrogen from alkanes.
32. A functional group is an atom or group of atoms that gives a molecule its characteristic properties.
33. On the basis of functional groups organic compounds are divided into different families.
34. Many organic compounds are used in perfumes, scents, paints, dyes and drugs.

COMPOUNDS NAME WITH THEIR FORMULAS:

1. Acetaldehyde CH₃-CHO
2. Acetic acid CH₃COOH OR CH₃-CO-OH
3. Acetone (Dimethyl ketone) CH₃-CO-CH₃
4. Ammonium cyanate NH₄CN
5. Benzene C₆H₆
6. Carbon disulphide CS₂
7. Chloroform CHCl₃
8. Dimethyl ether H₃C-O-CH₃
9. Diethyl ether C₂H₅-O-C₂H₅
10. Dimethyl amine H₃C-NH-CH₃
11. Ethene C₂H₆ OR CH₃=CH₃
12. Ethyne OR Acetylene C₂H₂ OR HC=CH
13. Ethyl acetate H₃C-CO-OC₂H₅
14. Ethyl alcohol CH₃-CH₂-OH
15. Ethyl methyl ether H₃C-O-C₂H₅
16. Ethyl methyl ketone H₃C-CO-CH₂-CH₃
17. Formaldehyde H-CO-H
18. Formic acid H-CO-OH
19. Glucose C₆H₁₂O₆
20. Methyl acetate H₃C-CO-OCH₃
21. Methyl alcohol CH₃-OH
22. Methyl amine H₃C-NH₂
23. Propyne CH₃-C=CH
24. Silicon Si
25. Trimethyl amine (CH₃-)₃N
26. Urea NH₂-CO-NH₂

ABBREVIATIONS:

• CNG Compressed natural gas