1. Keeping in view the size of atoms, which order is the correct one?

(A) Mg >Sr (B) Ba > Mg (C) Lu > Ce (D) Cl > I

2. Which one does not belong to alkaline earth metals?
(A) Be (B) Ra (C) Ba (D) Rn
3. Which metal is used in the thermite process because of its activity:
(A) iron (B) copper (C) aluminum (D) zinc
4. Out of all the elements of group VA, the highest ionization energy is possessed by the element:
(A) N (B) P (C) Sb (D) Bi
5. Which of the following hydrogen halide is the weakest acid in the solution:
(A)HF (B) HCl (C) HBr (D) HI
6. Which of the following is a non-typical transition element:
(A) Cr (B) Zn (C) Mn (D) Fe
7. The type of hybridization of carbon atom in methane is:
(A) sp3 (B) sp (C) sp2 (D) dsp2
8. Formula of chloroform is:
(A) CH3Cl (B)CH2Cl2 (C)CHCl3 (D)CCl4
9. Molecule of benzene contains:
(A) Three double bonds (B) Two double bonds
(C) One double bond (D) Delocalized π -electron charge
10. In primary alkyl halides, the halogen atom is attached to a carbon which is further attached to
how many carbon atoms:
(A) Two (B) Three (C) One (D) Four
11. Which compound shows hydrogen bonding:
(A) C2H6 (B) C2H6Cl (C) C2H5OH (D) CH3-O-CH3
12. The carbon atom of the carbonyl group is:
(A) sp hybridized (B) sp2 hybridized (C) sp3 hybridized (D) none of these
13. Acetic acid is manufactured by:
(A) Distillation (B) Fermentation (C) Ozonolysis (D) Esterification
14.In which of these processes are small organic molecules made into macromolecules:
(A) The cracking of petroleum fraction (B) The fractional distillation of crude oil
(C) The polymerization of ethene (D) The hydrolysis of protein
15. The three elements needed for the healthy growth of plants are:
(A) N, S, P (B) N, Ca, P (C) N, P, K (D) N, K, C
16. The pH range of acid rain is:
(A) 6.5 to 7 (B) 6.5 to 6 (C) 5.6 to 6 D) 5 to 4(less than 5)
17. Peroxy acetyl nitrate (PAN) is an irritant to human beings and it affects:
(A) Eyes (B) Ears (C) Stomach (D) Nose
18. Mark the correct statement:
(A) Na+ is smaller than Na atom (C) Na+ is large than Na atom
(B) Cl- smaller than Cl atom (D) Cl (ion) and Cl (atom) are equal in size
19. The oxide of beryllium is:
a. Acidic (B) basic (C) amphoteric (D) none of these
20. Aluminum oxide is:
a. acidic oxide (B) basic oxide (C) amphoteric oxide (D) none of these
21. Among group VA elements, the most electronegative elements is:
a. Sb (B) N (C) P (D) As
22. Chlorine heptaoxide (Cl2O7) reacts with water to form:
a. Hypochlorous acid (B)Perchloric acid
b. Chloric acid (D) Chlorine and oxygen
23. Which is a typical transition metal:
a. Se (B) Y (C) Ra (D) Co
 24. In t-butyl alcohol, the tertiary carbon is bonded to:
a. Three hydrogen atoms (C) Two hydrogen atoms
b. One hydrogen atom (D) No hydrogen atom
25. Preparation of vegetable ghee involves:
a. dehydrogenation (B) hydrogenation
b. halogenation (D) hydroxylation
26. Aromatic hydrocarbons are the derivatives of:
a. normal series of paraffins (B) alkene
b. benzene (D) cyclohexane
27. The reactivity order of akyl halides for a particular alkyl group is:
a. Fluoride> Chloride> Bromide>Iodide (B) Chloride> Bromide> Fluoride>
Iodide
(C)Iodide > Bromide >Chloride > Fluoride (D) Bromide>Iodide> Chloride>Fluoride
28. Which compound shows maximum hydrogen bonding with water:
a. CH3OH (B) C2H5OH (C) C6H5OH (D) CH3-O-CH3
29. Formalin is a mixture of:
a. 80% HCHO, 10% CH3OH and 10% H2O (B)8% HCHO, 40% CH3OH and 52% H2O
b. 40% HCHO 8% CH3OH and 52% H2O (D)None of these
30. A carboxylic acid contains:
a. A hydroxyl group (B) A carboxyl group
b. A hydroxyl and a carboxyl group (D) A carboxyl and aldehydic group
31. Which of these polymers is an addition polymer?
a. Nylon 6,6 (B) polystyrene (C) Terylene (D) epoxy resin
32. Which woody raw material is used for the manufacture of paper pulp?
a. Cotton (B) Bagasse (C) Poplar (D) Rice straw
33. A single chloride free radical can destroy how many ozone molecules:
a. 100 (B) 10,0000 (C) l0,000 (D) 10
34. Fungicides are the pesticides which:
a. Control the growth of fungus (B) Kill insects
b. Kill plants (D) Kill herbs
35. Mark the correct statement.
(A)All lanthanides are present in the same group
(B)All halogens are present in the same period
(C)All the alkali metals are present in the same group
(D)All the noble gases are present in the same period
36. Which ion will have the maximum value of heat of hydration:
(A)Na+ (B)Cs+2 (C)Ba+2 (D)Mg+2
37. Chemical composition of colemanite is :
a. Ca2B6O11.5H2O (B) CaB4H7.4H2O (C) CaNaB5O9.8H2O (D)
Na2B4O7.4H2O
38. Oxidation of NO in air produces:
(A)N2O (B) N2O3 (C) N2O4 (D) N2O5
39. Hydrogen bond is the strongest between the molecules of:
(A)HF (B) HCl (C) HBr (D) HI
40. f-block elements are also called:
a. non-typical transition elements (B) outer transition elements
b. normal transition elements (D) none is true
41. Which set of hybrid orbitals has planar triangular shape?
a. sp3 (B) sp (C) sp2 (D) dsp2
42. The presence of double or triple bond in a compound is the sign of:
 a. Unsaturation (B) saturation (C) addition (D)
substitution
43. Which acid can be used as a catalyst in Friedel-Crafts reaction?
a. AlCl3 (B) HNO3 (C) BeCl2 (D) NaCl
44. The reaction of ethyl magnesium iodide with carbon dioxide followed by acid hydrolysis gives:
a. Propane (B) propanal (C) propanoic acid (D) none
45. Which compound is more soluble in water:
a. CH3OH (B) C2H5OH (C) CH3COCH3 (D) n-hexanol
46. Which of the following compound will have the highest boiling point?
a. Methanal (B) Ethanal (C) Propanal (D) 2-Hexanone
47. Which acid is used in the manufacture of synthetic fiber?
a. Formic acid (B) Oxalic acid (C) Carbonic acid (D) Acetic acid
48. Which one is a synthetic polymer:
a. Polyester (B) Cellulose (C) Starch (D) Animal fat
49. The nitrogen present in fertilizers helps plants:
a. To fight against disease (C) To produce fat
b. To produce protein (D) To produce carbohydrate
50. To avoid the formation of toxic compounds with chlorine, the substance used for disinfecting water
is:
a. KMnO4 (B) Ozone (C) Alums (D) Chloramines
51. Ecosystem is a smaller unit of:
a. Lithosphere (B) Atmosphere (C) Biosphere (D)
Hydrosphere
52. Which statement is incorrect?
(A)All the metals are good conductor of electricity (B)All the metals are good conductor of
heat
(C)All the metals form positive ions (D)All the metals form acidic oxides
53. Which is not an alkali metal?
a. Francium (B) Cesium (C) Rubidium (D) Radium
54. Which element forms an ion with charge +3:
a. Carbon (B) Silicon (C) Aluminum (D) Beryllium
55. The brown gas formed when metal reduces HNO3 is:
a. N2O (B) N2O5 (C) NO2 (D) NO
56. Which halogen reacts spontaneously with Au(s)to produce Au3+?
a. Br2 (B) F2 (C) I2 (D) Cl2
57. The strength of binding energy of transition elements depends upon:
a. Number of electron pairs (B) Number of unpaired electrons
b. Number of neutrons (D) Number of protons
58. The chemist who synthesized urea from ammonium cyanate was:
a. Berzelius (B) Kolbe (C)Wohler (D) Lavoisier
59. Vinyl acetylene combines with HCI to form:
a. Polyacetylene (B) Divinylacetylene (C) Chloroprene (D)
Butane
60. Benzene cannot undergo:
a. substitution reactions (B) addition reactions
(C)oxidation reactions (D) elimination reaction
61. Grignard reagent is reactive due to:
a. the presence of Mg atom (B) the presence of halogen atom
b. the polarity of C-Mg bond (D) C-C bond
62. Ketones are prepared by the oxidation of:
a. primary alcohols (B) secondary alcohols
 b. tertiary alcohols (D) none of these
63. Which compound will have the maximum repulsion with H2O:
a. C6H6 (B) C2H5OH (C) CH3-O-CH3 (D)
CH3CH2CH2OH
64. The derivative of carboxylic acid cannot be prepared directly:
(A)Acetamide (B) Acetyl chloride (C) Acetic anhydride (D)
Ester
65. Plastics are a pollution problem because many plastics are:
a. very inflammable (B) made from Petroleum
b. burns to toxic fumes (D) decompose to produce toxic products
66. Phosphorus helps the growth of:
a. root (B) leave (C) stern (D) seed
67. The main pollutant of leather tanneries in the waste water is due to the salts of:
a. lead (B) chromium (VI) (C) copper (D) chromium (III)
68. In purification of potable water, the coagulant used is:
a. Nickel Sulphate (B) Copper Sulphate (C) Barium Sulphate (D) Alum
69. Which statement is incorrect?
a. Hydrogen resembles in properties with IA, IV and VIIA elements
b. Hydrogen resembles in properties with IIIA, IVA and VA elements
c. Hydrogen resembles in properties with IIA, IVA and VIA elements
d. Hydrogen resembles in properties with IIA, IIIA and VII A elements
70. The sulphate compound insoluble in water is:
a. Barium sulphate (B) Sodium sulphate (C) Potassium sulphate (D) Zinc sulphate
71. Which electronic configuration corresponds to an element of Group-IIIA of the periodic table:
a. 1s2 2s2 2p6 3s2 3p1 (B) 1s22s22p63s23p64s2
(C)1s2 2s2 2p6 (D) 1s2 2s2 2p6 3s2 3p3
72. Chemical formula of laughing gas is:
a. NO (B) N2O (C) NO2 (D) N2O4
73. The anhydride of HClO4 is:
a. ClO3 (B)ClO2 (C) Cl2O5 (D)Cl2O7
74. Group VI B of transition elements contains.
a. Zn, Cd, Hg (B) Fe, Fu, Os (C) Cr, Mo, W (D) Mn, Te, Re
75. Linear shape is associated with which set of hybrid orbitals?
(A)sp3 (B)sp (C)sp2 (D) dsp2
76. The addition of unsymmetrical reagent to an unsymmetrical alkene is in accordance with the rule:
a. Markovnikov’s rule (B) Pauli’s exclusion principle
b. Aufbau Principle (D) Hund's rule
77. Amongst the following compound that can be most readily sulphonated is:
a. Toluene (B) Benzene (C) Nitrobenzene (D) Chlorobenzene
78. SN2 reaction can be best carried out with:
a. Primary alkyl halides (B) secondary alkyl halides
b. Tertiary alkyl halides (D) All of these
79. Acetone reacts with HCN to form cyanohydrin. It is an example of:
a. Electrophilic addition (B) Electrophilic substation
b. Nucleophilic addition (D) Nucleophilic substitution
80. Ethanol can be converted into ethanoic acid by:
a. Hydrogenation (B) Hydration (C) Oxidation (D) Fermentation
81. Which reagent is used to reduce a carboxylic group to an alcohol?
a. H2 / Ni (B) H2 / Pt (C) H2 / Pd (D) LiAlH4
82. The fiber which is made from acrylonitrile as monomer is:
a. PVC (B) Rayon fiber (C) Acrylic fiber (D)Polyester fiber
 83. Micronutrients are required in quantity ranging from:
a. 4-40 g (B) 6-200 g (C) 6-200 kg (D) 10-200 kg
84. The temperature of the non- rotating chamber in the incineration of industrial and hazardous waste
process has a
range:
a. 950 to 1300 °C (B) 900 to 1000 °C (C) 250 to 500 °C (D) 500 to 900 °C
85. How many times the newspaper can be recycled?
a. 3 (B) 5 (C) 4 (D) 2
86. Mark the correct statement?
a. The ionization energy of calcium is lower than that of barium.
b. The ionization energy of calcium is lower than that of magnesium.
c. The ionization energy of calcium is higher than that of beryllium.
d. The ionization energy of calcium is lower than that of strontium.
87. The element cesium bear resemblance with:
a. Ca (C)Cr
b. Both of these metals (D) none of these
88. Which element among the following belongs to Group IVA of the periodic table:
a. Barium (B) Iodine (C) Lead (D) Oxygen
89. Out of all the elements of group VI A, the highest melting and boiling points is shown by the element:
a. Te (B) Se (C) S (D) Pb
90. Bleaching powder may be produced by passing chlorine over:
a. Calcium carbonate (C) Hydrated calcium sulphate
b. Anhydrous calcium sulphate (D) Calcium hydroxide
91. Which is the formula of tetra-ammine chloronitroplatinum (IV) sulphate?
a. [Pt (NH3)4(NO2)]SO4 (C) [PtNO2CI(NH3)4]SO4
b. [PtCI (NO2) (NH3)4]SO4 (D) [Pt (NH3)4(NO2) CI]SO4
92. Double bond consists of:
a. Two sigma bonds (C) One sigma and one pi bond
b. One sigma and two pi bonds (D) Two pi bonds
93. Synthetic rubber is made by polymerization of:
a. Chloroform (B) Acetylene (C) Divinyl acetylene (D) Chloroprene
94. During nitration of benzene, the active nitrating agent is:
a. NO3 (B) NO2+ (C) NO2 (D) HNO3
95. Elimination bimolecular reaction involves kinetics:
a. 1st order (B) 2nd order (C) 3rd order (D) Zero order
96. Which enzyme is not involved in fermentation of starch?
a. Diastase (B) Zymase (C) Urease (D) invertase
97. Which compounds will not give iodoform test on treatment with I2/ NaOH?
a. Acetaldehyde (B) Acetone (C) Butanone (D) 3-Pentanone
98. The solution of the acid used for seasoning of food is:
a. Formic acid (B) Acetic acid (C) Benzoic acid (D) Butanoic acid
99. A polymeric substance that is formed in the liquid state and then hardened to a rigid solid is called as:
a. Fiber (B) Plastic (C) Polyamide resin (D) Varnish
100. During the manufacturing process of the cement the temperature of the decomposition zone goes
up to:
a. 600oC (B) 900oC (C) 1000oC (D) 1200oC
101. Disinfection of water by chlorine is done by the production of:
(A)NH2Cl (B) NCl3 (C) HOCl (D) NHCl2
102. Atmosphere contains carbon dioxide:
a. 0.01% (B) 0.02% (C) 0.03% (D) 0.04%
103. Mark the correct statement?
 a. Electron affinity is a measure of energy required to remove the electron.
b. Electron affinity is a measure of energy released by adding an electron.
c. Electron affinity is a measure of energy required to excite an electron.
d. Electron affinity is measure of energy released by removing an
104. Chile saltpeter has the chemical formula:
a. NaNO3 (B) KNO3 (C) Na2B4O7 (D) Na2CO3.H2O
105. Boric acid cannot be used:
a. As antiseptic in medicine (C) For washing eyes
b. In soda bottles (D) For enamels and glazes
106. SO3 is not absorbed in water directly to form H2SO4 because:
a. The reaction does not go to completion (B) The reaction is quite slow
b. The reaction is highly exothermic (D) SO3 is insoluble in water
107. The strongest acid is:
a. HClO (B) HClO2 (C) HClO3 (D) HClO4
108. The percentage of carbon in different types of iron products is in the order of:
a. Cast iron > wrought iron > steel (C) Wrought iron > steel > cast iron
b. Cast iron > steel > wrought iron (D) Cast iron = steel > wrought iron
109. Ethers show the phenomenon of:
a. Position isomerism (C) Metamerism
b. Functional group isomerism (D) cis –trans isomerism
110. β, β-Dichloroethylsulphide is commonly known as:
a. Mustard gas (B)Laughing gas (C) Phosgene gas (D) Bio gas
111. Which compound is the most reactive one?
a. Benzene (B) Ethene (C) Ethane (D) Ethyne
112. For which mechanism, the first step involved is the same:
a. El and E2 (B) E2 and SN2 (C) SN1 and E2 (D) E1 and SN1
113. Which compound is called a universal solvent?
a. H2O (B) CH3OH (C) C2H5OH (D) CH3-O-CH3
114. Which compound reacts with Tollen's reagent.
a. Acetone (B) Pentanone (C) Butanone (D) Ethanal
115. Organic compounds X and Y react together to form organic compound Z. What types of
compounds can X, Y and Z be? X Y Z
a. Alcohol ester acid
b. acid ester alcohol
c. ester acid alcohol
d. alcohol acid ester
116. Vegetable oils are:
a. Unsaturated fatty acids (C) Glycerides of unsaturated fatty acids
b. Glycerides of saturated fatty acids (D) Essential oils obtained from plants
117. The word paper is derived from which reedy plant?
a. Rose (B) Sunflower (C) Papyrus (D) Water Hyacinth
118. Following is better to disinfect water:
a. Cl2 (B) O2 (C) O3 (D)KMnO4
119. The residual ash after incineration of industrial waste is disposed of in a landfill, which is lined
with:
(A)Portland cement (B) Clay and plastic (C) Stone-ware
(D)Methyl silicone
120. Encircle the correct statement.
(A)Metallic character increases down the group
(B)Metallic character increases along a period
(C)Metallic character remains the same along a period.
 (D)Metallic character remains the same down the group
121. The ore CaSO4.2H2O has the general name:
a. Gypsum (B) Dolomite (C) Calcite (D) Epsom salt
122. Which element is not present abundantly in the earth's crust?
a. Silicon (B) aluminum (C) Sodium (D) oxygen
123. The catalyst used in manufacturing of H2SO4 by contact process is:
a. V2O5 (B) Fe2O3 (C) Ni (D) Pt
124. The halogen which occurs naturally in a positive oxidation state:
a. F (B) Cl (C) Br (D) I
125. The color of transition metal complexes is due to:
a. d-d-transition of electron (C) ionization
b. loss of s-electrons (D) paramagnetic nature of transition elements
126. Select from the following one which is alcohol:
a. CH3-CH2-OH (B) CH3-O-CH3 (C)CH3COOH (D) CH3-CH2-
Br
127. When methane reacts with chlorine in the presence of diffused light, the products obtained are:
a. Chloroform (C) Carbon Tetra Chloride
b. Chloromethane and dichloromethane (D) Mixture of a, b and c
128. The electrophile used for the Sulphonation of benzene is:
a. SO3 (B) SO3+ (C) HSO4+ (D) H2SO4
129. Alkyl halides are considered to be very reactive compounds towards nucleophiles because:
(A)they have an electrophilic carbon
(B)they have an electrophilic carbon and a good leaving group.
(C)they have an electrophilic carbon and a bad leaving group
(D)they have a nucleophilic carbon and a good leaving group.
130. Methyl alcohol is not used as:
a. as a solvent (C) as an anti-freezing agent
b. as substitute for petrol (D) for denaturing of ethyl alcohol
131. Cannizzaro's reaction in not given by:
a. Formaldehyde (C) Acetaldehyde
b. Benzaldehyde (D) Tri methyl acetaldehyde
132. An aqueous solution of an organic compound reacts with sodium carbonate to produce carbon
dioxide gas. Which
133. one of the following could be the organic compound:
a. CH2=CH-CH3 (B) CH3-CHO
b. CH3COOC2H5 (D) CH3-CH2-COOH
134. Which of the following elements is not present in all proteins:
a. Sulphur (B) Nitrogen (C) Carbon (D) Hydrogen
135. Which is not a calcareous material?
a. Lime (B) Clay (C) Marble (D) Marine
shell
136. Which gas is not a pollutant?
(A)SO2 (B)NO2 (C) CO (D) CO2
137. The thickness of atmosphere is:
a. 1500 km (B) 1000 km (C) 500 km (D) 100 km
138. Which one is true about the melting points of halogens:
a. Decrease down the group (B) Increase down the group
b. Remain same in group (D) First increase then decrease down the group
139. Down’s cell is used to prepare:
(A)Sodium metal (B) Sodium bicarbonate
(C)Sodium carbonate (D) Sodium hydroxide
140. Tincal is a mineral of:
(A)Al (B)Si (C)B (D)C
141. Which of the following species has the maximum number of unpaired electrons:
a. O2 (B) O2- (C) O2+ (D) O2-2
142. An element that has high ionization energy and tends to be chemically inactive would mostly
likely to be:
a. An alkali metal (B) A transition element
b. A noble gas (D) A Halogen
143. Coordination number of Pt in [PtCl (NO2) (NH3)4]
a. 2 (B) 4 (C) 1 (D) 6
144. Octane number 100 is given to:
a. n-octane (B) 2,2,4-trimethylpentane
b. n-heptane (D) 2,2,4-trimethytoctane
145. Which gas is used for artificial ripening of fruits?
a. Ethene (B) Ethyne (C) Methane (D) Propane
146. Aromatic compounds give sooty flame because they:
a. Resist the reaction with air (B) Contains high percentage of carbon
b. Have stable structure (D) Have a cyclic structure
147. The rate of E1 reactions depends upon:
a. The concentration of substrate
b. The concentration of nucleophile
c. The concentration of substrate as well as nucleophile
d. None of these
148. Rectified spirit is:
a. 80 % alcohol (B) 95% alcohol (C) 85% alcohol (D)
98% alcohol
149. Which of the following reagents will react with both aldehydes and Ketones?
a. Grignard reagent (B) Tollen's reagent (C) Fehling reagent (D) Benedict’s reagent
150. Which of the following is not a fatty acid?
a. propanoic acid (B) acetic acid (C) phthalic acid (D) butanoic
acid
151. Which of the following nitrogenous basses is not present in RNA:
a. Cytosine (B) Adenine (C) Thiamine (D) Uracil
152. The number of zones a rotary kiln during through which the charge passes in manufacture of
cement are:
a. 2 (B) 3 (C) 4 (D) 5
153. The fresh water being used for domestic purpose is:
a. 8% (B) 23% (C) 69% (D) 100%
154. The normal amount of overhead ozone is:
a. 300DU (B) 350 DU (C) 400 DU (D) 450 DU
155. Mark the correct statement.
a. Covalent character of metal halides increases from left to right in a period
b. Boiling points of Group IVA hydrides decrease down the group
c. Ionic character of hydrides increases from left to right in a period.
d. The basicity of group IIA oxides decreases on descending the group
156. The element deposited at the cathode during the electrolysis of brine in diaphragm cell:
a. Na (B)H2 (C)Cl2 (D) O2
157. The chief ore of aluminum is:
a. NaAlF3 (B) Al2O3.2H2O (C) Al2O3 (D) Al2O3.H2O
158. The % age by volume of N2 in air is:
a. 98 (B) 88 (C) 78 (D) 68
159. The correct electronic configuration of the outermost energy level of an element of zero (VIIIA)
group in the ground state?
a. s2p2 (B) s2p4 (C) s2p5 (D) s2p6
160. The total number of transition elements is:
a. 10 (B) 14 (C) 40 (D) 58
161. The boiling point range of petroleum ether is:
(A)5-20 Oc (B) 10-30 Oc (C) 20-60 oC (D) 30-90oC
162. Raney Nickel is:
a. Nickel compound (C) Naturally occurring nickel
b. Less active form of a nickel (D) Activated nickel by excitation
163. The conversion of n-hexane into benzene by heating in the presence of Pt is called:
a. Isomerism (B) Aromatization (C) Dealkylation (D) Rearrangement
164. Electrophile among the following is:
a. NH3 (B) H2O (C) BF3 (D) all of these
165. According to Lewis concept ethers are:
a. Acids (C) Bases
b. Acids as well as bases (D) Neither acids nor bases
166. Tollen's reagent is:
a. Alkaline solution containing potassium tartrate (C)alkaline solution containing
potassium citrate.
b. Ammoniacal AgNO3 solution (D) none of these
167. Acetamide is prepared by:
a. Heating ammonium acetate (C) Heating methyl cyanide
b. Heating ethyl acetate (D) hydrolysis of methyl cyanide
168. Which one of the following enzymes brings about the hydrolysis of fats?
a. Urease (B) Maltase (C) Zymase (D) Lipase
169. Ammonium nitrate fertilizer is not used for which crops?
a. Cotton (B) Wheat (C) Sugarcane (D) paddy rice
170. The residence time of NO in atmosphere is:
a. Thirty minutes (B) One day (C) Three days (D) Four days
171. Bio chemical oxygen demand is the capacity of organic matter in natural water to consume
oxygen with in a period of:
a. Three days (B) Four days (C) Five days (D) Six days