65. In an enzyme system, compound A is an inhibitor and it can be reversed by increasing concentration of the substrate B. The inhibition type is:
Correct Answer: B. Competitive reversible
Explanation: Competitive inhibitors compete with substrate. ↑[S] reverses inhibition.
66. Chlorine has 2 isotopes 35Cl and 37Cl. Which statement is true?
Correct Answer: B. They have same number of protons
Explanation: Isotopes = same Z, different N. Chemical properties same.
67. In an experiment, four plants are exposed to different temperatures and wind speeds. Which plant shows highest transpiration?
Correct Answer: B. Plant D
Explanation: High temp + high wind = maximum transpiration rate.
68. Which of the following is not a colligative property?
Correct Answer: C. Surface tension
Explanation: Colligative = depends on no. of particles only. Surface tension is not.
69. The pH of a 0.001 M HCl solution is:
Correct Answer: C. 3
Explanation: [H+] = 10⁻³ M → pH = -log[H+] = 3.
70. Which gas has the highest rate of diffusion?
Correct Answer: C. H₂
Explanation: Graham's Law: Rate ∝ 1/√M. H₂ has lowest molar mass = 2.
71. The hybridization of carbon in ethene C₂H₄ is:
Correct Answer: B. sp²
Explanation: C=C double bond → trigonal planar → sp².
72. Which element has highest ionization energy?
Correct Answer: D. Ne
Explanation: IE ↑ across period, ↓ down group. Noble gases highest.
73. 0.5 mole of NaCl dissolved in 1L water. Molarity =?
Correct Answer: B. 0.5 M
Explanation: M = moles/L = 0.5/1 = 0.5 M.
74. Which bond is most polar?
Correct Answer: C. O-H
Explanation: Electronegativity diff: O=3.5, H=2.1 → highest diff.
75. The oxidation state of Cr in K₂Cr₂O₇ is:
Correct Answer: B. +6
Explanation: 2(+1) + 2x + 7(-2) = 0 → 2+2x-14=0 → x=+6.
76. Which one is a strong acid?
Correct Answer: C. HCl
Explanation: HCl, HNO₃, H₂SO₄ are strong acids. Others weak.
77. At equilibrium, for a reaction: N₂ + 3H₂ ⇌ 2NH₃, Kp =?
Correct Answer: B. Kc(RT)⁻²
Explanation: Δn = 2-4 = -2. Kp = Kc(RT)^Δn.
78. Which has planar structure?
Correct Answer: C. BF₃
Explanation: BF₃ = sp², trigonal planar, 120° bond angle.
79. The number of moles in 44g CO₂ is:
Correct Answer: B. 1.0
Explanation: M(CO₂) = 44 g/mol. Moles = 44/44 = 1.
80. Which is not an allotrope of carbon?
Correct Answer: D. Methane
Explanation: Allotropes = same element diff forms. Methane is compound.
81. Electrolysis of NaCl(aq) gives at anode:
Correct Answer: C. Cl₂
Explanation: At anode oxidation: 2Cl⁻ → Cl₂ + 2e⁻.
82. The IUPAC name of CH₃-CH₂-OH is:
Correct Answer: B. Ethanol
83. Which has highest boiling point?
Correct Answer: D. C₄H₁₀
Explanation: BP ↑ with molecular mass for alkanes. Van der Waals ↑.
84. The shape of PCl₅ molecule is:
Correct Answer: C. Trigonal bipyramidal
85. Which reaction is redox?
Correct Answer: C. Zn + CuSO₄ → ZnSO₄ + Cu
Explanation: Zn 0→+2, Cu +2→0. Oxidation state change.
86. The volume of 1 mole gas at STP is:
Correct Answer: B. 22.4 L
87. Which is amphoteric oxide?
Correct Answer: C. Al₂O₃
Explanation: Amphoteric = reacts with acid + base. Al₂O₃, ZnO.
88. The rate of reaction doubles when temp ↑ 10°C. This is:
Correct Answer: B. Arrhenius Equation
89. Which compound shows H-bonding?
Correct Answer: C. NH₃
Explanation: H-bonding when H attached to N, O, F.
90. The conjugate base of H₂SO₄ is:
Correct Answer: B. HSO₄⁻
91. Which has highest lattice energy?
Correct Answer: B. MgO
Explanation: LE ∝ charge/radius. Mg²⁺O²⁻ has +2,-2 charges.
92. The functional group -COOH is:
Correct Answer: C. Carboxylic acid
93. 1 Faraday =? Coulombs
Correct Answer: A. 96500 C
94. Which is primary standard?
Correct Answer: C. K₂Cr₂O₇
Explanation: Primary standard = pure, stable, non-hygroscopic.
95. The pKa of a weak acid is 5. At pH 5, [A⁻]/[HA] =?
Correct Answer: B. 1
Explanation: Henderson: pH = pKa + log[A⁻]/[HA]. If pH=pKa, ratio=1.
96. Which metal does not react with water?
Correct Answer: D. Cu
Explanation: Cu is below H in reactivity series. No reaction.
97. The geometry of SF₆ is:
Correct Answer: C. Octahedral
98. Which is not a state function?
Correct Answer: C. Work
Explanation: State function = path independent. Work, heat are path functions.
99. The product of electrolysis of molten NaCl is:
Correct Answer: B. Na + Cl₂
100. Which has sp hybridization?
Correct Answer: A. CO₂
Explanation: CO₂ = O=C=O, linear, sp hybridization.
101. The solubility of gas ↑ when:
Correct Answer: B. Temp ↓, Pressure ↑
Explanation: Henry's Law: solubility ∝ P. Gas solubility ↓ with temp ↑.
102. The oxidation number of N in HNO₃ is:
Correct Answer: B. +5
Explanation: +1 + x + 3(-2) = 0 → x = +5.
103. Which is an addition polymer?
Correct Answer: C. Polyethene
104. The enthalpy change for combustion is:
Correct Answer: B. Exothermic
105. Which buffer has pH = pKa?
Correct Answer: A. [Acid] = [Salt]
106. The number of sigma bonds in ethene C₂H₄ =?
Correct Answer: C. 5
Explanation: C=C has 1σ+1π, 4 C-H = 4σ. Total = 5σ.
107. Which is most reactive metal?
Correct Answer: D. K
108. The formula of baking soda is:
Correct Answer: B. NaHCO₃
109. Which has highest electron affinity?
Correct Answer: B. Cl
Explanation: Cl > F due to less e⁻-e⁻ repulsion in 3p.
110. The catalyst used in Haber process is:
Correct Answer: B. Fe
111. Which is a Lewis acid?
Correct Answer: C. BF₃
Explanation: Lewis acid = e⁻ pair acceptor. BF₃ has empty p-orbital.
112. The order of reaction can be:
Correct Answer: C. Fractional
113. Which gas is used in welding?
Correct Answer: C. Ar
Explanation: Argon is inert gas used to prevent oxidation.
114. The ΔH for H₂O(l) → H₂O(g) is:
Correct Answer: B. Positive
Explanation: Vaporization requires heat → endothermic → +ΔH.
115. Which has coordinate bond?
Correct Answer: C. NH₄⁺
Explanation: NH₃ donates lone pair to H⁺ → dative bond.
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