Hydride ion = H^- = 1s²

Benzene has the following resonancestructures -

Hence , is it bond order is 1.5 .

According to fajan's rule , AgCl is themost covalent compound among these ,hence is the least ionic .

Among halogens , the order of elctronaffinity is -

Cl > F > Br > I

Unexpectedly , florine has less electronaffinity than chlorine .It is due to greaterelctron density on F (lesser size) due towhich it fends to repel the incomingelectron .

In a group , ionsation energy decreases aswe move down .Hence Li has maximumfirst ionisation energy among these .

The molecular orbital elctronic configuration of O₂ is -

O₂ (16e^-) = $\mathrm{\sigma }$1s² , $\mathrm{\sigma }$1s² , $\mathrm{\sigma }$2s² , $\mathrm{\sigma }$2s² , $\mathrm{\sigma }$2p_x² , $\mathrm{\pi }$2p_y², $\mathrm{\pi }$2p_z² , $\mathrm{\pi }$2p_y¹ , $\mathrm{\pi }$2p_z¹

Hence , it has two unpaired lectrons and is paramagnetic .

Tritium is only redioactive isotope ofhydrogen .Its nucleus is an stable (n/pratio = 2.0) .

The favourable conditions for melting ofice are high temperature and highpressure according to Le-chatelierprinciple .

Ice$\rightleftharpoons$water

In exothermic reactions heat is alwaysgiven out by the reaction .For exothermicreactions -

$\mathrm{\Sigma }$H_R >$\mathrm{\Sigma }$H_P

$\because$One mole of Sn²⁺car reduce$\frac{1}{3}$moles of K₂Cr₂O₇ .