Medium Practice — Set 1

Quick Recap — Ordering Trends

• Inert pair effect grows down a group: +3 stable for Al, +1 for Tl; +4 for C, +2 for Pb.
• $HX$ acidity: HF $<$ HCl $<$ HBr $<$ HI; thermal stability: HF $>$ HCl $>$ HBr $>$ HI; reducing power: HI $>$ HBr $>$ HCl $>$ HF.
• Oxidising power of halogens: $F_2>Cl_2>Br_2>I_2$; bond enthalpy: $Cl_2>Br_2>F_2>I_2$ (F$_2$ anomalously low).
• Basicity of group-15 hydrides: $NH_3>PH_3>AsH_3>SbH_3$; oxyacid acidity of Cl: $HClO_4>HClO_3>HClO_2>HClO$.