$\mathrm{Cu}_{(\mathrm{s})}+2 \mathrm{H}_{(\mathrm{aq})}^{+} \longrightarrow \mathrm{Cu}_{(\mathrm{aq})}^{+2}+\mathrm{H}_{2(\mathrm{~g})}$

$\mathrm{H}_{2(\mathrm{~g})}+\mathrm{Cu}_{(\mathrm{aq})}^{+2} \longrightarrow 2 \mathrm{H}_{(\mathrm{aq})}^{+}+\mathrm{Cu}_{(\mathrm{s})}$

$\mathrm{Cu}_{(\mathrm{s})}+\mathrm{H}_{2(\mathrm{~g})} \longrightarrow \mathrm{Cu}_{(\mathrm{aq})}^{+2}+2 \mathrm{H}_{(\mathrm{aq})}^{+}$

$\quad \mathrm{Cu}_{(\mathrm{aq})}^{+2}+2 \mathrm{H}_{(\mathrm{aq})}^{+} \longrightarrow \mathrm{Cu}_{(\mathrm{s})}+\mathrm{H}_{2(\mathrm{~g})}$

Tetracyanonickelate (II) ion

Sodiumhexafluoraluminate (III)

Triamminetrinitrocobalt (III)

Tetraamminecopper (II) ion

Nylon 6

Nylon 6,6

Terylene

Neoprene

$(-q \wedge p) \wedge(p \wedge \sim p)$

$(p \wedge q) \wedge(\sim p \wedge q)$

$[(\sim q) \wedge p] \wedge q$

$(\sim q \wedge p) \vee(p \vee \sim p)$