2019 MI Prelim H2 Chem P1 ANS

Q1 Option 1: Amount of H2SO4 = 0.5 x 1 = 0.5 mol H2SO4 → 2H+ + SO42- Amount of H+ = 0.5 x 2 = 1 mol Option 2: Amount of SO3 molecules = 6 / 24 = 0.25 mol 1 SO3 molecule has 4 atoms (1 S and 3 O atoms) Amount of atoms = 0.25 x 4 = 1 mol Option 3: Amount of SO2 molecule = 64.1 / (32.1 + 16.0 x 2) = 1 mol 1 SO2 molecule has 16 + 8 x 2 = 32 electrons Amount of electrons = 1 x 32 = 32 mol Option 4: Amount of S8 molecule = 1.6 /(32.1 x 8) = 0.00623 mol 1 S8 molecule has 16 x 8 = 128 neutrons Amount of neutrons = 0.798 mol Ans: 1 and 2 are correct => A Q2 CH3CH2CH2OH + 4O2 → 2CO2 + CO + 4H2O Since mole ratio = volume ratio of gases, Vol of O2 consumed = 4y Ans: B Q3 [R] MnO4- + 4H+ + 3e- → MnO2 + 2 H2O [O] Mn2+ + 2H2O → MnO2 + 4H+ + 2e- 2MnO4- + 3Mn2+ + 2H2O → 2MnO2 + 3MnO2 + 4H+ 2 mol of MnO4- reacts with 3 mol of Mn2+ 1 mol of MnO4- reacts with 1.5 mol of Mn2+ Ans: C

Q4 Z2+ has 12 electrons and 15 neutrons Z has 14 electrons, 14 protons and 15 neutrons=> Ar = 14 + 25 = 39 Option A: angle of deflection ∝ charge mass charge mass for Z2+ = +𝟐 𝟏𝟒+𝟏𝟓 = +𝟐 𝟐𝟗 charge mass for Mg2+ = +𝟐 𝟐𝟒.𝟑 charge mass for Mg2+ > charge mass for Z2+ Angle of deflection for Mg2+ > Angle of deflection for Z2+ Option A is correct Option B: Based on the proton number, Z is referring to Silicon. Si has a higher IE than Al (Group 13 element in the same period as Z) => You can check from Data Booklet or recall from the trend across the period. Option C: SiCl4 has a lower melting point than MgCl2 as SiCl4 has a simple molecular structure while MgCl2 has a giant ionic structure. Larger amount of energy is needed to overcome the stronger electrostatic forces of attraction between Mg2+ and Cl- than the weaker instantaneous dipole-induced dipole forces of attraction between SiCl4 molecules. Option D: Element Z has 14 electrons while neon has 10 electrons. Hence, they are not isoelectronic.

Q5 All options have simple molecular structures. Option 1 and 4 have instantaneous dipole-induced dipole forces of attraction between molecules Option 2 has hydrogen bonding between molecule Option 3 has permanent dipole-permanent dipole forces of attraction between molecules. Hence option 2 will be the highest followed by option 3 For option 1 and 4, the two molecules are isomers of each other. Thus, the surface area determines the boiling point. Since option 1 is a straight-chained molecule, it has a larger surface area between molecules which results in stronger instantaneous dipole-induced dipole forces of attraction than that of option 4 since option 4 is a branched-chain molecule. Hence option 4 as the lowest boiling point. Boiling point: 4 < 1 < 3 < 2 => Option D is correct Q6 The N highlighted in yellow has 6 electrons from N hence this N has a charge of -1. The N highlighted in turquoise has 5 electrons from N hence thus N has