Balance arrow

In chemistry , equilibrium reactions are marked with a double arrow ⇌, where each arrow only has half a point.

This is also known as the balance arrow. The forward reaction runs from left to right. The reverse reaction from right to left. There is a chemical equilibrium when, in a reversible chemical reaction, back and forth reactions take place at the same speed .

Example:

${\displaystyle \mathrm {NH_{3}+H_{2}O\ \rightleftharpoons \ NH_{4}^{+}+OH^{-}} }$

A molecule of ammonia and a molecule of water are in equilibrium with an ammonium ion and a hydroxide ion.

The quantitative material composition of the equilibrium obeys the law of mass action .

Presentation on the computer

⇌

Unicode

In the international character coding system Unicode , the equilibrium arrow occupies position U + 21CC.

Individual evidence

1. ↑ Entry on chemical reaction equation . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.C01034 .