0% Chemistry- MDCATChemistry in MDCAT assesses essential chemical principles for medical fields. It is a core component of the standardised test for admission to Pakistani medical and dental colleges. The section evaluates understanding of organic, inorganic, and physical chemistry relevant to biological sciences. 1 / 100According to Le Chatelier's Principle, if the temperature is increased for an exothermic reaction at equilibrium, the equilibrium will shift: It will not shift First to the right, then to the left To the left, favoring reactants To the right, favoring products 2 / 100The complex ion [CoF₆]³⁻ is paramagnetic. The hybridization of cobalt in this complex is: d²sp³ sp³d² sp³ dsp² 3 / 100Which quantum number defines the shape of an orbital? Magnetic quantum number (m) Azimuthal quantum number (l) Spin quantum number (s) Principal quantum number (n) 4 / 100The process of a solid changing directly into a gas is called: Condensation Melting Evaporation Sublimation 5 / 100 The mass of one mole of electrons is approximately: 1.008 g 0.55 mg 9.1 g 0.184 g 6 / 100 In a face-centered cubic lattice, a unit cell is shared by how many unit cells? 4 6 8 2 7 / 100 The order of stability of the following carbocations is: (I) (CH₃)₃C⁺ (II) CH₃-CH₂⁺ (III) (CH₃)₂CH⁺ I > II > III III > II > I I > III > II II > III > I 8 / 100The number of isomers possible for C₄H₈ (excluding stereoisomers) is: 6 5 4 3 9 / 100 The symbol 'Na' represents the element: Neon Nitrogen Nickel Sodium 10 / 100In the decomposition of KClO₃ to KCl and O₂, 0.1 moles of KClO₃ produces how many grams of O₂? (O=16) 9.6 g 1.6 g 4.8 g 3.2 g 11 / 100The oxidation state of sulfur in H₂SO₄ is: +2 +6 -2 +4 12 / 100 Which hydrocarbon undergoes substitution reactions readily? Alkene All of these Alkyne Alkane 13 / 100The pH of 0.01 M CH₃COOH solution (Ka = 1.8 × 10⁻⁵) is approximately: 3.4 5.8 4.7 2.0 14 / 100The number of isomers possible for C₄H₁₀O (alcohols) is: 2 3 4 5 15 / 100The osmotic pressure of a 0.1 M solution of a non-electrolyte at 27°C (R=0.0821 L.atm/mol.K) is: 24.6 atm 0.246 atm 2.46 atm 1.23 atm 16 / 100Which sub-shell has the lowest energy? 4s 4p 5s 3d 17 / 100The reaction CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O is an example of: Saponification Hydrolysis Polymerization Esterification 18 / 100The crystal structure of NaCl is: Face-centered cubic Body-centered cubic Simple cubic Hexagonal close-packed 19 / 100The E° values for Fe³⁺/Fe²⁺ and I₂/I⁻ are +0.77 V and +0.54 V respectively. The feasibility of the reaction 2Fe³⁺ + 2I⁻ → 2Fe²⁺ + I₂ is: At equilibrium Spontaneous Non-spontaneous Cannot be predicted 20 / 100 The catalyst used in the Haber process for ammonia synthesis is: Vanadium pentoxide Iron with promoters Platinum Nickel 21 / 100In a face-centered cubic (FCC) crystal lattice, the number of atoms per unit cell is: 1 6 2 4 22 / 100Which halogen exists as a liquid at room temperature? Chlorine Iodine Fluorine Bromine 23 / 100The rate of a chemical reaction generally: Decreases with increase in temperature Is unaffected by temperature Increases with increase in temperature First increases then decreases 24 / 100What is the charge on a proton? Variable Neutral Negative Positive 25 / 100The process used for the purification of copper is: Roasting Smelting Electrolytic refining Calcination 26 / 100Which quantum number determines the shape of an orbital? Azimuthal quantum number Spin quantum number Principal quantum number Magnetic quantum number 27 / 100The correct order of reactivity towards nucleophilic substitution reaction for the following is: (I) CH₃-CH₂-Cl (II) (CH₃)₂CH-Cl (III) CH₃-CH₂-Br I > III > II II > I > III I > II > III III > I > II 28 / 100The half-life of a first-order reaction is 10 minutes. The time required for the concentration to decrease from 0.1 M to 0.025 M is: 10 minutes 30 minutes 40 minutes 20 minutes 29 / 100Which of the following has the highest boiling point? CH₄ C₂H₆ C₃H₈ C₄H₁₀ 30 / 100The vertical columns in the periodic table are called: Rows Groups Periods Blocks 31 / 100The percentage of s-character in the hybrid orbitals of ethane, ethene, and ethyne follows the order: Ethyne > Ethane > Ethene Ethene > Ethane > Ethyne Ethyne > Ethene > Ethane Ethane > Ethene > Ethyne 32 / 100Which of the following has the highest boiling point? HCl CH₄ NH₃ H₂O 33 / 100What is the atomic number of an element with 12 protons and 12 neutrons? 24 6 12 18 34 / 100The shape of a water molecule is: Trigonal planar Tetrahedral Bent Linear 35 / 100Which compound will exhibit geometrical isomerism? CH₂=CH₂ CH₃-C≡C-CH₃ CH₃-CH=CH₂ CH₃-CH=CH-CH₃ 36 / 100The pH of a neutral solution at 25°C is: 7 3 9 11 37 / 100Which salt solution has pH greater than 7? NaCl CH₃COONa CuSO₄ NH₄Cl 38 / 100A solution with a pH of 3 is how many times more acidic than a solution with a pH of 5? 100 times 2 times 1000 times 10 times 39 / 100The order of reactivity of halogens in halogenation of alkanes is: I₂ > Br₂ > Cl₂ > F₂ Br₂ > Cl₂ > F₂ > I₂ F₂ > Cl₂ > Br₂ > I₂ Cl₂ > F₂ > Br₂ > I₂ 40 / 100The compound that gives a positive Tollens' test but negative Fehling's test is: Acetone Benzaldehyde Formaldehyde Acetaldehyde 41 / 100The compound that will undergo the Cannizzaro reaction is: Benzaldehyde Formalin Acetone Acetaldehyde 42 / 100The hybridization of carbon in ethyne (C₂H₂) is: sp² sp dsp² sp³ 43 / 100The catalyst used in the Contact Process for sulfuric acid manufacture is: Platinum Iron Vanadium pentoxide Nickel 44 / 100Which of the following is a noble gas? Chlorine Neon Oxygen Nitrogen 45 / 100 According to Boyle's law, at constant temperature: V ∝ T V ∝ n P ∝ 1/V P ∝ T 46 / 100The half-life of a first-order reaction is 10 minutes. The time taken for the concentration of the reactant to decrease from 1.0 M to 0.125 M is: 20 minutes 40 minutes 10 minutes 30 minutes 47 / 100 The density of a gas is 2.0 g/L at 1 atm pressure and 27°C. Its molecular mass is: 22.4 44.8 49.2 64.5 48 / 100The atomic number of an element is defined as the number of: Protons and neutrons Neutrons only Protons only Electrons only 49 / 100The crystal field splitting energy (Δo) for an octahedral complex is: Zero for transition metal complexes Inversely proportional to the charge on the central metal ion Directly proportional to the charge on the central metal ion Independent of the charge on the central metal ion 50 / 100Which subatomic particle is located in the nucleus of an atom? Neutron only Proton and Neutron Electron only Proton only 51 / 100In the electrochemical series, the standard electrode potential is measured relative to: Standard hydrogen electrode Silver-silver chloride electrode Zinc electrode Calomel electrode 52 / 100The general formula for alkanes is: CₙHₙ CₙH₂ₙ₋₂ CₙH₂ₙ CₙH₂ₙ₊₂ 53 / 100The mass of 2.24 L of CO₂ gas at STP is: 22 g 4.4 g 2.2 g 44 g 54 / 100The Haber process is used for the industrial production of: Sulfuric Acid Ammonia Urea Nitric Acid 55 / 100In the electrolysis of aqueous CuSO₄ using copper electrodes, the: Concentration of CuSO₄ increases Concentration remains the same pH decreases Concentration of CuSO₄ decreases 56 / 100 Which of the following is a compound? Iron Oxygen Water Air 57 / 100Which of the following is a strong electrolyte? Sugar solution Ethanol Acetic acid Sodium chloride solution 58 / 100The shape of a methane (CH₄) molecule is: Trigonal Planar Bent Tetrahedral Linear 59 / 100The boiling point of water at 700 mmHg pressure is: Less than 100°C 100°C More than 100°C 0°C 60 / 100The number of possible structural isomers for C₇H₁₆ is: 10 9 11 8 61 / 100The bond angle in a water molecule is approximately: 120° 180° 109.5° 104.5° 62 / 100The chemical formula for water is: CO₂ H₂O O₂ NaCl 63 / 100For a reaction: 2A + B → Products, when concentration of B is doubled, the rate doubles. When concentration of A is doubled, the rate becomes four times. The rate law is: Rate = k[A][B] Rate = k[A]²[B]² Rate = k[A][B]² Rate = k[A]²[B] 64 / 100The IUPAC name for CH₃-CH₂-CHO is: Ethanal Butanal Propanal Propanone 65 / 100The unit of molarity is: mol/kg g/L ppm mol/L 66 / 100The process used to convert vegetable oils into fats is: Saponification Hydrogenation Halogenation Oxidation 67 / 100Which of the following is an example of a covalent network solid? Diamond Sodium chloride Ice Copper 68 / 100 The magnetic moment of [Fe(CN)₆]⁴⁻ is: 0 BM 4.90 BM 1.73 BM 2.83 BM 69 / 100In the reaction: Zn + 2HCl → ZnCl₂ + H₂, zinc acts as: Catalyst Reducing agent Oxidizing agent Electrolyte 70 / 100How many electrons can the first shell (K-shell) of an atom hold? 1 2 3 0 71 / 100The number of π-bonds in benzene is 12 3 6 9 72 / 100The number of moles in 44 grams of CO₂ (C=12, O=16) is: 2 0.5 1 3 73 / 100A compound contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen. Its empirical formula is: CH₂O C₃H₆O₃ C₆H₁₂O₆ C₂H₄O₂ 74 / 100The number of atoms in 4.2 g of nitrogen gas (N₂) is: 1.204 × 10²⁴ 3.612 × 10²³ 6.02 × 10²³ 1.806 × 10²³ 75 / 100The standard enthalpy of formation (ΔH°f) for which of the following substances is zero? C(diamond) CO₂(g) H₂O(l) O₂(g) 76 / 100A covalent bond is formed by the: Donation of protons Transfer of electrons Sharing of electrons Sharing of protons 77 / 100The rate constant of a reaction is 2.3 × 10⁻⁵ L mol⁻¹ s⁻¹. The order of reaction is: 4 5 2 3 78 / 100Which complex shows optical isomerism? [Pt(NH₃)₂Cl₂] [Co(en)₃]³⁺ [Co(NH₃)₆]³⁺ [Co(NH₃)₅Cl]²⁺ 79 / 100Which of the following is a homogeneous mixture? Sugar solution Soil Sand and water Milk 80 / 100For a reaction, ΔG is negative. This means the reaction is: At equilibrium Spontaneous Non-spontaneous Fast 81 / 100The rate law for a reaction is found to be Rate = k [A]²[B]. If the concentration of A is doubled and B is halved, the rate of reaction will: Become four times Become double Remain the same Become half 82 / 100The pH of a neutral solution at 25°C is: 10 7 0 14 83 / 100Which state of matter has a definite volume but no definite shape? Plasma Gas Solid Liquid 84 / 100 A buffer solution is prepared by mixing: Strong base and its salt Weak base and a strong acid Weak acid and its salt Strong acid and its salt 85 / 100The IUPAC name of CH₃-CH₂-CH(CH₃)-CHO is: Pentanal 2-Methylbutanal 2-Ethylpropanal 3-Methylbutanal 86 / 100According to the Kinetic Molecular Theory, the pressure of a gas is due to: The collision of gas molecules with the container walls The weight of the gas molecules The volume occupied by the gas molecules The attraction between gas molecules 87 / 100The SI unit of pressure is: Atmosphere Pascal Torr Bar 88 / 100In a chemical reaction, the substance that is completely consumed first is called the: Limiting reactant Product Catalyst Excess reactant 89 / 100The reagent used to distinguish between aldehyde and ketone is: NaHCO₃ Br₂ water Fehling's solution Litmus solution 90 / 100Which element shows the phenomenon of allotropy? Magnesium Calcium Sodium Carbon 91 / 100 The number of σ and π bonds in CH₂=CH-C≡N are: 7σ, 2π 5σ, 3π 6σ, 3π 8σ, 1π 92 / 100The E° value for the standard hydrogen electrode is assigned a value of: 0.00 V 1.00 V -1.00 V 2.00 V 93 / 100 The chemical formula of gypsum is: CaCO₃ CaSO₄ CaSO₄·½H₂O CaSO₄·2H₂O 94 / 100The oxidation state of chromium in K₂Cr₂O₇ is: +2 +7 +4 +6 95 / 100Which halogen is a liquid at room temperature? Iodine Chlorine Fluorine Bromine 96 / 100In the electrolysis of molten NaCl, the product at the cathode is: Chlorine gas Oxygen gas Hydrogen gas Sodium metal 97 / 100A substance that turns blue litmus paper red is: A salt An acid A base Neutral 98 / 100The process by which a solid changes directly into vapor without passing through the liquid state is called: Fusion Evaporation Sublimation Condensation 99 / 100Which element has the highest electronegativity? Chlorine Oxygen Nitrogen Fluorine 100 / 100 Which alcohol gives iodoform test? Methanol n-Butanol Benzyl alcohol Ethanol Your score isThe average score is 68% 0% Restart quiz