What are the applications of displacement reactions?

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Answer 1 · 2014-04-12T15:41:59

Some applications of displacement reactions are thermite welding, steel making, extraction of metals, and relief from acid indigestion.

A single displacement reaction is often of the type

$A + BC \to B + AC$ $"A + BC → B + AC"$

In this reaction, element $A$ $"A"$ replaces element $B$ $"B"$ in the compound $BC$ $"BC"$ .

Here are a few examples of the practical applications of displacement reactions.

Thermite Welding

A mixture of $Al$ $"Al"$ and ${Fe}_{2} O_{3}$ $"Fe"_2"O"_3$ reacts to produce molten iron that is used to join railway rails together.

$2Al + {Fe}_{2} O_{3} \to {Al}_{2} O_{3} + 2Fe$ $"2Al" + "Fe"_2"O"_3 → "Al"_2"O"_3 + "2Fe"$

Al replaces $Fe$ $"Fe"$ in ${Fe}_{2} O_{3}$ $"Fe"_2"O"_3$ to form ${Al}_{2} O_{3}$ $"Al"_2"O"_3$ .

www.sec.gov

$"CADWELD"^®$ process

A mixture of $"Al"$ and $"CuO"$ is used for creating electric joints between $"Cu"$ and steel.

$"2Al" + "3CuO" → "3Cu" + "Al"_2"O"_3$

$"Al"$ replaces $"Cu"$ in the $"CuO"$ .

www.nimbus-lightning.co.uk

Steel Making

We can extract iron from its ore ( $"Fe"_2"O"_3$ ) by heating it with carbon in giant blast furnaces.

$"3C" + "2Fe"_2"O"_3 → "4Fe" + "3CO"_2$

$"C"$ replaces $"Fe"$ in $"Fe"_2"O"_3$ to form $"CO"_2$ .

www.chemguide.co.uk

Extraction of Metals

Heating a mixture of $"Cr"_2"O"_3$ and finely divided $"C"$ produces metallic chromium.

$"3C" + "2Cr"_2"O"_3 → "4Cr" + "3CO"_2$

$"C"$ replaces $"Cr"$ in $"Cr"_2"O"_3$ to form $"CO"_2$ and chromium metal.

Acid Indigestion

We can relieve the distress when the stomach produces too much $"HCl"$ by drinking a solution of sodium hydrogen carbonate.

$"HCl" + "NaHCO"_3 → "NaCl" + "H"_2"CO"_3$

The $"H"$ in the $"HCl"$ displaces the $"Na"$ in $"NaHCO"_3$ to produce $"H"_2"CO"_3$ .