Basic Concepts in Chemistry MCQs – II

101)A chemical equation is balanced according to the law of
a) multiple proportions
b) reciprocal proportions
c) conservation of mass
d) definite proportions

102)A gas is found to have the formula . Its V.D is 70. The value of x must be
a) 7
b) 4
c) 5
d) 6

103)In chlorine gas, ratio of is
a) 1:3
b) 3:1
c) 1:1
d) 1:4

104) The equivalent mass of sulphur in is
a) 8
b) 16
c) 64.8
d) 32

105)0.5 g of a metal on oxidation gave 0.79 g of its oxide. The equivalent weight of the metal is
a) 10
b) 14
c) 20
d) 40

106)74.5 g of a metallic chloride contains 35.5 g of chlorine. The equivalent weight of the metal is
a) 19.5
b) 35.5
c) 39.0
d) 78.0

107)The chloride of a metal (M) contains 65.5% of chlorine. 100 ml. of the vapor of the chloride of the metal at S.T.P weigh 0.72 g. the molecular formula of the metal chloride is
a) MCl

108)The equivalent weight of a metal is 4.5 and the molecular weight of its chloride is 80. The atomic weight of the metal is
a) 18
b) 9
c) 4.5
d) 36

109)The sulphate of an element contains 42.2% element. The equivalent weight would be
a) 17.0
b) 35.0
c) 51.0
d) 68.0

110)The equivalent weight of an element is 4, its chloride has a vapour density 59.25, then the valency of the element is
a) 4
b) 3
c) 2
d) 1

111)The oxide of an element possesses the formula . If the equivalent weight of the metal is 9, then the atomic weight of the metal will be
a) 9
b) 18
c) 27
d) none of these

112)The approximate atomic weight of an element is 29.89. If its equivalent weight is 8.9, the exact atomic weight is
a) 26.89
b) 8.9
c) 17.8
d) 26.7

113)0.534 g Mg displaces 1.415 g Cu from the salt solution of Cu. Equivalent weight of Mg is 12. The equivalent weight of Cu would be
a) 15.9
b) 47.7
c) 31.8
d) 8.0

114)An element X reacts with oxygen to form a compound . If the atomic weight of X is 129.24, the equivalent weight of X is
a) 47.9
b) 49.7
c) 43.08
d) 51.0

115)In gram of a metal A displaces gram of another metal B from its salt solution and if the equivalent weights are and respectively then the equivalent weight of A can be expressed by

116) The equivalent weight of ( in acid medium) is (at. wt. of K= 39, Mn=55)
a) 158
b) 15.8
c) 31.6
d) 3.16

117)The equivalent weight of iron in would be
a) 18.6
b) 28
c) 56
d) 112.0

118)The equivalent weight of as an oxidizing agent in acid medium is
a) 2/3 of its mol.wt
b) 1/3 of its mol. Wt
c) 1/6 of its mol . wt
d) ½ of its mol. Wt

119)Equivalent weight of I2 in the reaction is
a) M
b) M/2
c) M/5
d) M/10

120)In the reaction equivalent weight of iodine will be equal to
a) its molecular weight
b) ½ of its molecular weight
c) ¼ of its molecular weight
d) twice the molecular weight

121)The equivalent weight of Mohr’s salt is equal to its
a) molecular weight
b) 1/4 of mol. wt
c) 1/2 mol. wt.
d) 1/10 mol.wt.

122)The equivalent weight of when it is converted into is
a) M/5
b) M/6
c) M/3
d) M/2

123) The weights of two elements which combine with one another are in the ratio of their
a) atomic weight
b) molecular weight
c) gram mole
d) equivalent weight

124) Which of the following is not a correct chemical equation?

125) The weight of iron which will be converted into its oxide by the action of 18 g of steam on it will be ( at. wt. of Fe = 56)
a) 168g
b) 84g
c) 42g
d) 21g

126) If Al, Zn and Fe scraps had the same rate per Kg, then for the production of by action of dilute
a) Fe will be cheapest and AI will be costliest
b) AI will be cheapest and Zinc will be costliest
c) Fe will be cheapest and Zinc will be costliest
d) Zn will be cheapest and AI will be costliest

127)10 g of a piece of marble was put into excess of dilute HCl acid. When the reaction was complete, of was obtained at STP. The percentage of in the marble is

128)20cc of are passed over red hot coke. The volume of evolved is
a) 10cc
b) 20cc
c) 30cc
d) 40cc

129)Consider the following data:
Element       Atomic weight
A                     12
B                     35.5
A and B combine to form a new substance X. If four atoms of B combine with one mole of A to give one atom of X then the weight of one molecule of X is

a) 47.5 g
b) 83g
c) 154 g
d) 166g

130)27 g of AI (at. mass=27) will react completely with oxygen equal in weight to
a) 24 g
b) 8 g
c) 40 g
d) 10g

131)The number of moles of required for reacting with 6.8g of ammonia

a) 5
b) 2.5
c) 1
d) 0.5

132)The total number of electrons in 18 ml of water (density of water is ) is

133)M is the molecular weight of . The equivalent weight of In a reaction where it is converted into is
a) M
b) M/3
c) M/5
d) M/7

134)If moles of oxygen combine with Al to form ,the weight of Al used in the reaction is (at. wt. 27
a) 27 g
b) 53 g
c) 40.5 g
d) 81 g

135) If 0.5 mol of is mixed with 0.2 mol of , the maximum number of moles of that can be formed is
a) 0.7
b) 0.5
c) 0.30
d) 0.10

136)A compound (60 g) on analysis gave C= 24 g, H= 4 g, O= 32 g. Its empirical formula is

137)What quantity of limestone on heating will give 56 kg of CaO?
a) 1000 Kg
b) 56 Kg
c) 44Kg
d) 100 Kg

138)Which one of the following properties of an element is not variable?
a) Valency
b) Atomic number
c) Equivalent weight
d) All of the above

139)Among the known elements, the maximum number is of
a) metals
b) non-metals
c) metalloids
d) none of the above

140)Which of the following weighs the least?
a) 2 g atom of N (at. wt . of N= 14 )
c) 1 mole of S (at. wt of S= 32)
d) 7 g silver (at. wt of Ag = 108)

141)The empirical formula of an organic compound containing carbon and hydrogen is . The mass of one litre of this organic gas is exactly equal to that of one litre of . Therefore, the molecular formula of the organic gas is

142)19.7 Kg of gold was recovered from a smuggler. How many atoms of gold were recovered? (Au=197)
a) 100

143)The oxide of a metal has 32% oxygen. Its equivalent weight would be
a) 34
b) 32
c) 17
d) 16

144)3.92 g/l of a sample of ferrous ammonium sulphate reacts completely with solution. The percentage purity of the sample is
a) 50
b) 78.4
c) 80.0
d) 39.2

145)A molar solution is one that contains one mole of a solute in
a) 1000 g of the solvent
b) one litre of the solvent
c) one litre of the solution
d) 22.4 litres of the solution

146)74.5 g of a metallic chloride contains 35.5 g of chlorine. The equivalent weigh
a) 19.5
b) 35.5
c) 39.0
d) 78.0

147)From among the following three, members of which combinations have an identical number of molecules? Chose from the option given.

a) I and II
b) II and III
c) I and III
d) I,II and III

148)1 mol of contains
b) 4 g atoms of hydrogen
d) 3.0 g of carbon

149)The molecular weight of hydrogen peroxide is 34. What is the unit of molecular weight?
a) g
b) mol

150)Which property of an element is always a whole number?
a) atomic weight
b) Equivalent weight
c) Atomic number
d) Atomic volume

151)If two compounds have the same empirical formula but different molecular formulae, they must have
a) Different percentage composition.
b) Different molecular weights.
c) Same viscosity
d) Same vapor density.

152)The density of gas A is three times that of gas B. If the molecular weight of A is M, molecular weight of B is
a) 3M
c) M/3

153)The number of electrons in a mole of hydrogen molecules is
d) indefinite.

154)Which of the following has the smallest number of molecules?

155)Which one of the following pairs of gases contains the same number of molecules?

156)@ The equivalent weight of an element is 3. Its chloride has a vapor density of 77. The valency of the element is
a) 4
b) 3
c) 2
d) 1

157)Avogadro Number is
a) the number of atoms in one gram of element.
b) the number of millilitres which one mole of a gaseous substance occupies at N.T.P.
c) the number of molecules present in one gram molecular mass of substance.
d) All the above.

158)At S.T.P the density of vapour in g/L will be nearest to
a) 6.84
b) 3.42
c) 10.26
d) 4.57

159)One litre of hard water contains . How many milli-equivalents of washing soda would be required to remove its hardness?
a) 1
b) 12.6

160)1 c.c. of at NTP contains:
d) none of the above.

161)When potassium permanganate is titrated against ferrous ammonium sulphate, the equivalent weight of potassium permanganate is
a) molecular weight /10
b) molecular weight /5
c) molecular weight/2
d) molecular weight

162)@ A metal oxide has the formula . It can be reduced by hydrogen to give the free metal and water. 0.1596 g of the metal oxide required 6 mg of hydrogen for combination.
a) 27.9
b) 159.6
c) 79.8
d) 55.8

163)The weight of molecules of is
a) 41.59 g
b) 415.9 g
c) 4.159 g
d) none of the three

164)@ The sulphate of a metal contains 20% of M. This sulphate is isomorphous with . The atomic weight of M is
a) 12
b) 24
c) 36
d) 48

165)Two elements X (atomic weight = 75) and Y (atomic weight = 16) combine to give a compound having 75.8% of X. The formula of the compound is

166)A 5 molar solution of is diluted from 1 litre to a volume of 10 litres, the normality of the solution will be
a) 1N
b) 0.1 N
c) 5N
d) 0.5 N

167)1.25 g of a solid dibasic acid is completely neutralized by 25 mL of 0.25 molar solution. The molecular mass of the acid is
a) 100
b) 150
c) 120
d) 200

168)100 ml of 1.0 M HCl are mixed with 75 ml of 1.0 M . The resulting solution will be
a) Acidic
b) Basic
c) Neutral
d) Amphoteric

169)The number of moles of which contains 1.5 moles of oxygen atoms is
a) 0.5
b) 1
c) 3

170)The equivalent weight of is half its molecular weight when it is converted to

171)The law of multiple proportions was proposed by
a) Lavoisier
b) Dalton
c) Proust
d) Gay-Lussac

172)A solution containing and NaOH required 300 mL of 0.1 N HCl using phenolphthalein as an indicator. Methyl Orange is then added to the above titrated solution when a further 25 mL of 0.2 N HCl is required. The amount of NaOH = 40,
a) 0.8 g
b) 1.0 g
c) 1.5 g
d) 2.0 g

173)What quantity of ammonium sulphate is necessary for the production of gas sufficient to neutralize a solution containing 292 g of HCl ? [ HCl = 36.5;

a) 272 g
b) 408 g
c) 528 g
d) 1056 g

174)0.115 g of pure sodium metal was dissolved in 500 mL distilled water. The normality of the solution would be [ Na = 23]
a) 0.010 N
b) 0.00115 N
c) 0.023 N
d) 0. 046 N

175)1) Out of the following three, members of which combination have the same mass? Chose the right answer from the option given



a) I and II
b) II and III
c) I and III
d) I,II and II

176)One litre of a gas at STP weighs 1.16 g. It can possibly be
b) CO

177)How many millilitres (mL) of solution is required to neutralize 10 mL of solution?
a) 2.5 mL
b) 5.0 mL
c) 10.0 mL
d) 20.0 mL

178)Rearrange the following ( I to V) in the order of increasing masses and choose the correct answer from (a) , (b), (c) and (d) ( atomic mass: N= 14, O= 16, Cu = 63)

    1. 1 molecule of oxygen
    2. 1 atom of nitrogen


179)In the reaction the equivalent weight of (mol. Wt = M ) is equal to
a) M
b) M/2
c) M/3
d) M/4

180)If the equivalent weight of a trivalent metal is 32.7 the empirical formula weight of its chloride is
a) 68.2
b) 103.7
c) 204.6
d) 32.7

181)The simplest formula of a compound containing 50% of element X( atomic mass 10) and 50% of element Y (atomic mass 20) is
a) XY

182)If is number then number of valence electrons in 4.2 g of nitride ions is

183)In the final answer of the expression the number of significant figures are
a) 1
b) 2
c) 3
d) 4

184)One fermi is

185)@ In a chemical reaction the values of x, y, z are
a) 1,3,1
b) 4,1,4
c) 3,2,3
d) 2,1,2

186)The hydrogen phosphate of a certain metal has formula . The formula of the metal chloride would be
a) MCl

187)A sample was weighed using two different balances. The results were (i) 3.929 g (ii) 4.0 g. How would the weight of the sample be reported ?
a) 3.929 g
b) 3 g
c) 3.9 g
d) 3.93 g

188)Dimensions of pressure are same as that of
a) Energy
b) Force
c) Energy per unit volume
d) Force per unit volume

189)The vapour density of a gas is 11.2. The volume occupied by 11.2 g of the gas at NTP will be
a) 11.2 L
b) 22.4 L
c) 1L
d) 44.8 L

190)The mass of a molecule of water is

191)The amount of Zinc required to produce 224 ml of at STP on treatment with dilute will be
a) 0.65 g
b) 6.5 g
c) 65 g
d) 0. 065 g

192)Which of the following is not a mixture ?
a) wax
b) brass
c) iodized salt
d) air

193)1 amu is equal to

194)For preparing 0.1 N solution of a compound from its impure sample of which the percentage purity is known, the weight of the substance required will be
a) more than the theoretical weight
b) less than the theoretical weight
c) the same as the theoretical weight
d) none of the above

195)16 g of has the same number of molecules as in
d) Both a and c

196)The volume occupied by 4.4 g of CO2 at STP is
a) 22.4 l
b) 2.24 l
c) 0.224 l
d) 0.1 l

197)The maximum amount of precipitated on mixing equal volumes of (0.5 M) with (1 M) will correspond to
a) 0.5 M
b) 1.0 M
c) 1.5 M
d) 2.0 M

198)Given the numbers : 161 cm, 0.161 cm, and 0.0161 cm, the number of significant figures for the three numbers are
a) 3,4 and 5 respectively.
b) 3,3 and 3 respectively
c) 3,3 and 4 respectively
d) 3,4 and 4 respectively

199)@ Haemoglobin contains 0.33 % of iron by weight. The molecular weight of Haemoglobin is approximately 67200. The number of iron atoms ( at. Wt of Fe = 56) present in one molecule of haemoglobin is
a) 6
b) 1
c) 4
d) 2

200)In the reaction when 1 mole of ammonia and 1 mole of are made to react to completion
b) 1.0 mole of NO will be produced
c) all the oxygen will be consumed
d) all the ammonia will be consumed.