NJC 2023 A Level Chem Solution

H2 Chemistry TYS 2023 Paper 1 1 H2 Chemistry TYS 2023 suggested answers Paper 1 Answer Key 1 B 11 D 21 A 2 C 12 D 22 B 3 C 13 C 23 A 4 D 14 C 24 B 5 B 15 B 25 D 6 D 16 C 26 B 7 A 17 C 27 D 8 C 18 C 28 A 9 A 19 A 29 B 10 A 20 C 30 C 1 Ans: B Nucleon number Proton Neutron Electron Nd2+ 145 60 85 58 Pm3+ 145 61 84 58 2 Ans: C Ionic compound has a large electronegativity difference between the elements while covalent compound has small difference in electronegativity. A X and Cl Electronegativity difference = 1.8 Y and O Electronegativity difference = 2.6 B X and O Electronegativity difference = 2.3 Y and O Electronegativity difference = 2.6 C Y and Cl Electronegativity difference = 2.1 Z and O Electronegativity difference = 1.7 D Z and Cl Electronegativity difference = 1.2 X and Cl Electronegativity difference = 1.8 3 Ans: C Both CH3Cl and CH3Br are covalent compound with simple molecular structure. Both are polar molecules with instantaneous dipole-induced dipole (id-id) and permanent dipole-permanent dipole (pd-pd) between molecules. As CH3Br has a larger electron cloud size, its electron cloud is more easily distorted, and dipoles are more easily induced. The strength of id-id is stronger for CH3Br, leading to its larger boiling point.

H2 Chemistry TYS 2023 Paper 1 2 4 Ans: D NH4+ 4 single bonds, 8 shared e− CO2 2 double bonds, 8 shared e− HCHO 1 double bond + 2 single bonds 8 shared e− 5 Ans: B 1,1-difluroethene cis-1,2-difluroethene trans-1,2-difluroethene tetrafluroethene 6 Ans: D Period 3 elements with only one orbital in the outermost shell which contains just one electron: 1) Na : [Ne] 3s1 2) Al : [Ne] 3s2 3p1 3) Cl : [Ne] 3s2 3p5 (one of the 3p orbital contains only 1 e−) Period 3 elements with only one orbital in the outermost shell which contains a pair of electrons: 1) Mg : [Ne] 3s2 2) Al : [Ne] 3s2 3p1 3) Si : [Ne] 3s2 3p2 (e− occupies the p orbital singly first) 4) P : [Ne] 3s2 3p3 (e− occupies the p orbital singly first)

H2 Chemistry TYS 2023 Paper 1 3 7 Ans: A Statement 1 is correct. Going down Group 2, Eꝋ(M2+/M) becomes more negative. This shows that Ba(s) undergoes oxidation more readily than Mg(s). Hence Ba(s) is a stronger reducing agent than Mg(s). Statement 2 is correct. Down the group, cationic radius increases and charge density of M2+ decreases. This leads to a decrease in polarising power of the cations. The electron cloud of the CO32− anion is being distorted to a smaller extent down the group, decreasing the extent of weakening of C–O bonds within the CO32− anion. More energy is required to break the C–O bonds within the CO32− anion. Therefore, thermal stability of the Group 2 carbonates increases down the group. Statement 3 is incorrect. Down the group, cationic radius increases and charge density of M2+ decreases. 8 Ans: C The least c