Lithium - 3Li: reactions of elements
Reaction of lithium with air
Lithium metal is quite easily cut with a knife. The result is a shiny silvery surface but this soon tarnishes because of reaction with oxygen and moisture from the air. When lithium is burned in air, the main product is the white oxide lithium oxide, Li2O. Some lithium peroxide, Li2O2, also white, is also produced.
4Li(s) + O2(g) → 2Li2O(s)
2Li(s) + O2(g) → 2Li2O2(s)
Lithium also reacts with nitrogen, N2, to form lithium nitride, Li3N. None of the other Gruop 1 elements do anything similar, but magnesium (Gruop 2) similarly forms a nitride.
6Li(s) + N2(g) → 2Li3N(s)
Reaction of lithium with water
Lithium metals reacts slowly with water to form a colourless solution of lithium hydroxide (LiOH) and hydrogen gas (H2). The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic, but the reaction is slower than that of sodium (immediately below lithium in the periodic table).
2Li(s) + 2H2O → 2LiOH(aq) + H2(g)
Reaction of lithium with the halogens
Lithium metal reacts vigorously with all the halogens to form lithium halides. So, it reacts with fluorine, F2, chlorine, Cl2, bromine, I2, and iodine, I2, to form respectively lithium(I) fluoride, LiF, lithium(I) chloride, LiCl, lithium(I) bromide, LiBr, and lithium(I) iodide, LiI.
2Li(s) + F2(g) → LiF(s)
2Li(s) + Cl2(g) → LiCl(s)
2Li(s) + Br2(g) → LiBr(s)
2Li(s) + I2(g) → LiI(s)
Reaction of lithium with acids
Lithium metal dissolves readily in dilute sulphuric acid to form solutions containing the aquated Li(I) ion together with hydrogen gas, H2.
2Li(s) + H2SO4(aq) → 2Li+(aq) + SO42-(aq) + H2(g)
Reaction of lithium with bases
Lithium metals reacts slowly with water to form a colourless solution of basic lithium hydroxide (LiOH) and hydrogen gas (H2). The reaction continues even when the solution becomes basic. The resulting solution is basic because of the dissolved hydroxide. The reaction is exothermic, but the reaction is slower than that of sodium (immediately below lithium in the periodic table). As the reaction continues, the concentration of the hydroxide increases.
2Li(s) + 2H2O → 2LiOH(aq) + H2(g)