81. One mole of oxygen gas at STP is equal to
(A) 6.022 x 1023 molecules of oxygen
(B) 6.022 x 1023 atoms of oxygen
(C) 16 g of oxygen
(D) None of these
Ans. (C)
82. Which of the following has maximum number of unpaired electrons?
(A) Mg2+ (B) Ti3+
(C) V3+ (D) Fe2+
Ans. (D)
83. The electronegativity of C, N, Si and P are in the order of
(A) Si < P < C <N (B) Si < P < N < C
(C) P < Si < N < C (D) P < Si < C < N
Ans. (A)
84. Which of the following substance has dipole moment more than zero?
(A) Water (B) Nitrogen
(C) Methane (D) Carbon dioxide
Ans. (A)
85. Which set of conditions represents the easiest way to cool a gas?
(A) Low temperature and low pressure
(B) Low temperature and high pressure
(C) High temperature and low pressure
(D) High temperature and high pressure
Ans. (A)
86. Heat exchanged in a chemical reaction at constant temperature and pressure is called
(A) Free energy (B) Entropy
(C) Enthalpy (D) Internal energy
Ans. (C)
87. The concentration of hydrogen in a sample of soft drink is 3.8 x 10-3 M. The pH of the solution is
(A) 2.42 (B) 2.84
(C) 3.36 (D) 4.24
Ans. (A)
88. In the reaction : 2 Ag + 2H2SO4 -> Ag2SO4 + 2H2O + SO2 Sulphuric acid acts as
(A) Catalyst
(B) Oxidizing agent
(C) Reducing agent
(D) Acid as well as oxidant
Ans. (D)
89. Which of the following compounds is used for water softening?
(A) Na2HPO4 (B) Na2P6O18
(C) Na3PO4 (D) Ca3 (PO4)2
Ans. (B)
90. The formula of soda ash is
(A) Na2 CO3 (B) Na2CO3 · H2O
(C) Na2CO3 · 2H2O (D) Na2CO3 · 10H2O
Ans. (A)
91. Which is the anhydride of nitrous acid?
(A) NO (B) N2O4
(C) N2O3 (D) N2O
Ans. (D)
92. Which belongs to alkyne series?
(A) C16H32 (B) C9H16
(C) C10H22 (D) C7H14
Ans. (B)
93. The highest boiling point is expected for
(A) Iso-butane
(B) n-butane
(C) n-octane
(D) 2, 2, 3, 3-tetramethly butane
Ans. (C)
94. BOD is a measure of
(A) Organic pollutant in water
(B) Inorganic pollutant in water
(C) Particle matter in water
(D) None of these
Ans. (A)
95. Which is also known as dislocation defect?
(A) Simple interstitial defect
(B) Non – stoichiometric defect
(C) Schottky defect
(D) Frenkel defect
Ans. (D)
96. 2.5 litre of 1M NaOH solution is mixed with 3.0 litres of 0.5 M NaOH solution. The molarity of the resulting solution is
(A) 0.73 M (B) 0.82 M
(C) 1.06 M (D) 1.12 M
Ans. (A)
97. The conductivity of 0.01 M NaCl solution is 0.00147 ohm-1 cm-1.What happens to the conductivity if extra 100 ml is added to the above solution?
(A) Increases
(B) Decreases
(C) Remain same
(D) First increases and then decreases
Ans. (B)
98. The rate of a chemical reaction becomes double for every 100 rise in temperature. If the temperature is raised by 500 C, the rate of reaction increasing by about
(A) 32 times (B) 44 times
(C) 64 times (D) 112 times
Ans. (A)
99. The catalyst used for preparing Grignard reagent is
(A) Activated charcoal (B) Iron powder
(C) Jodine powder (D) Manganese dioxide
Ans. (C)
100. The process of converting hydrated alumina into anhydrous alumina is called
(A) Roasting (B) Calcination
(C) Dressing (D) Smelting
Ans. (B)
