Sindh MDCAT 2026 Past Paper 81- Phenol primarily undergoes which type of reaction on its aromatic ring? A. AdditionB. EliminationC. Electrophilic substitutionD. Nucleophilic substitution View Answer Answer : C. Electrophilic substitution Description 82- The solubility of CaCl2 is 0.02 mol L⁻¹. Its Ksp is: A. 1.6 × 10⁻⁵B. 3.2 × 10⁻⁵ C. 6.4 × 10⁻⁵D. 8.0 × 10⁻⁶ View Answer Answer : B. 3.2 × 10⁻⁵ Description 83- For gases at identical temperature and pressure, which contains the greatest number of molecules? A. 1 dm³ HeB. 2 dm³ NeC. 1 dm³ N2D. 3 dm³ O2 View Answer Answer : D. 3 dm³ O2 Description 84- The oxidation state of hydrogen in BeH2 is: A. +1B. 0C. -1D. -2 View Answer Answer : C. -1 Description 85- Alkali metals react with water to form: A. Metal hydride + O2B. Metal hydroxide + H2C. Metal oxide + oxygenD. Metal peroxide + H2O View Answer Answer : B. Metal hydroxide + H2 Description 86- The IUPAC name of CH3CH(CH3)CH2CH(CH2CH3)CH3 is: A. 2,4-DimethylhexaneB. 3-Ethyl-2-methylpentaneC. 2,4-DimethylheptaneD. 3,5-Dimethylheptane View Answer Answer : A. 2,4-Dimethylhexane Description 87- Which substituent is strongly ortho/para directing? A. -CNB. -COOHC. -CHOD. -OH View Answer Answer : D. -OH Description 88- A gas occupies 400 mL at 226°C. What volume will it occupy at 127°C at constant pressure? A. 267 mLB. 300 mLC. 321 mLD. 500 mL View Answer Answer : C. 321 mL Description 89- 64 g CH4 occupies 44.8 L at 2 atm. Its approximate temperature is: A. 127 KB. 273 KC. 373 KD. 546 K View Answer Answer : B. 273 K Description 90- Anisotropy means that a property: A. Is independent of directionB. Is independent of temperatureC. Varies with directionD. Is independent of pressure View Answer Answer : C. Varies with direction Description 91- Phenol treated with excess nitrating mixture gives: A. NitrobenzeneB. 2-Nitrophenol onlyC. 2,4,6-TrinitrophenolD. Benzoic acid View Answer Answer : C. 2,4,6-Trinitrophenol Description 92- Which statement correctly compares ethene and ethyne hybridization? A. Ethene is sp and ethyne is sp²B. Ethene is sp² and ethyne is spC. Both are sp³D. Both are sp View Answer Answer : B. Ethene is sp² and ethyne is sp Description 93- The reactant that is completely consumed first and determines the maximum amount of product is called: A. Excess reactantB. CatalystC. Limiting reactantD. Intermediate View Answer Answer : C. Limiting reactant Description 94- A capacitor has capacitance C = 2 μF and is charged to V = 12 V. What is the charge q stored on it? A. 2.4 × 10⁻⁵ C B. 2.4 × 10⁻⁶ CC. 1.2 × 10⁻⁵ CD. 6 × 10⁻⁶ C View Answer Answer : A. 2.4 × 10⁻⁵ C Description 95- Compared with reactants, products of an exothermic reaction generally have: A. Zero enthalpyB. Equal enthalpyC. Lower enthalpyD. Higher enthalpy View Answer Answer : C. Lower enthalpy Description 96- Which of the following decreases activation energy? A. Increasing pressureB. Increasing temperatureC. Adding a catalystD. Increasing concentration View Answer Answer : C. Adding a catalyst Description 97- If doubling [A] doubles the rate and doubling [B] increases the rate fourfold, the rate law is: A. Rate = k[A]²[B]B. Rate = k[A][B]C. Rate = k[A]²[B]²D. Rate = k[A][B]² View Answer Answer : D. Rate = k[A][B]² Description 98- If Rate = k[A]²[B], and both [A] and [B] are tripled, the rate becomes: A. 3 timesB. 9 timesC. 27 timesD. 81 times View Answer Answer : C. 27 times Description 99- Which does NOT change the position of a chemical equilibrium? A. Change in pressureB. Change in concentrationC. Change in temperatureD. Addition of a catalyst View Answer Answer : D. Addition of a catalyst Description 100- The decomposition of N2O5 is commonly treated as: A. Zero orderB. First orderC. Second orderD. Third order View Answer Answer : B. First order Description 1 2 3 4 5 6 7 8
