Pada penyetaraan reaksi kimia, jumlah atom pada ruas kiri dan ruas kanan harus sama. Langkah yang digunakan untuk penyetaraan reaksi kimia yaitu:
1. Pemberian koefisien reaksi pada setiap zat
![size 14px aP subscript size 14px 4 size 14px plus size 14px bCl subscript size 14px 2 size 14px rightwards arrow size 14px cPCl subscript size 14px 5](data:image/png;base64,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)
2. Penentuan persamaan matematika berdasarkan unsur yang sama
(1)
(2)
3. Perhitungan koefisien a, b, dan c
Perhitungan koefisien a, b, dan c dilakukan dengan melakukan pemisalan pada salah satu koefisien, misal a=1, maka :
![begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 4 a end cell equals c row cell 4 left parenthesis 1 right parenthesis end cell equals c row c equals 4 end table end style](data:image/png;base64,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)
![begin mathsize 14px style table attributes columnalign right center left columnspacing 0px end attributes row cell 2 b end cell equals cell 5 c end cell row cell 2 b end cell equals cell 5 left parenthesis 4 right parenthesis end cell row b equals cell 20 over 2 end cell row b equals 10 end table end style](data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAD4AAABbCAYAAAAr+DatAAAACXBIWXMAAA7EAAAOxAGVKw4bAAAABGJhU0UAAAAs8vz+fQAAA0xJREFUeNrtnDFoFEEUhgeRQ0IIyHEECRIIwSqFEMRCDhGChYQQAiIWFoetvQSxt5QQ0oqICCGIiNilspUjpAghYGEhIaQJFrIcgfMN/gt3e7Ozs3Fmbmb3ffATdrO5m7fzZnffP7MR4h/LpG+kHn5ukSbFMH3hnn6OnPGFdJd0CdtPSTtjCnysyBPwp46Bz5J+KBp1H/vPSI8vmLa69DUNfJ60jXY8sxn4Z9KqolEfSNeREa9Jdxz0uLzO/CK9J91UHHML7ZvBdWjTxhdP4gtXDHpjirTrKOMmcOK7pKXM776jx60xjR6dL5GGieVUz9Ii7WX29WwGfZX0ET9NLzwz6BGXyKw6zOw7Is3ZHNMLBuPvFU7OFQyJJcuBvsGFVSC4T6RHmWMekL6SrpEaaJPTB4ffpIekA9JP0j0HPSyfH06Rzl3NneMGnj2OSU8EwzAMwzBMJKyTXpQ4dr0KQa+goCqDsuqMyXO7DDOkqTkpqrY2UeA0BnfG5LnJtm1oqswDzeds4O9zCdlz20GGqniHwibvc5YVHTpEyJ7biWIYpkFtF3zOBKo/bX0equd2npPi+wPjXncClQ5ODJ6bKvC3pDXDzBkJPBbP7RgnvezdIO3Yk2yqxOK56S5uRT0+cnGLyXPT3c6KApcefKdsqoTiuTXwINIsGfg0sqfBj6wRFymmhcdL0nOu6xiGYRiGYRxhYoAKmCFdHCdL2HbsgZsYoHMoPBaxvSgsLxUJAZUBuilGXdOOsLQELBRUBqjcbmX2NVE2VwaVAXqec2yvCgHrDNC8wJPYgy4yQI8Uqd5SDImoMDFARzw0bG/FPqaLDND0dpZOPNxGb1u9nfleS27qlbfx4JIalG0XDakltQ7c9WxpsIG7ni2NItVdzZb2LcvJGE/qkuqD+JgtDSZw17OlQeJjtpRhhjH14SqHiQ9XC1Q+XC2Yjd10+J+afbVOAet8uMpS5MNVEhMfrrJjekHUkOgrPYZhGIZhGMb146IP5P94kW8U7GmO8bq2zVfg8v3Qjub7vK9t6weSYd7XtvmeJs47xvvaNt/TxHmBe1/b5vOl2osEnvhsSDKGVPe+ts33NLHx+6HC8do239PERbczp2vbBvE1TexlbdtfElCNIfF0Hn0AAAKPdEVYdE1hdGhNTAA8bWF0aCB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMTk5OC9NYXRoL01hdGhNTCIgY2xhc3M9Indyc19jaGVtaXN0cnkiPjxtdGFibGUgY29sdW1uYWxpZ249InJpZ2h0IGNlbnRlciBsZWZ0IiBjb2x1bW5zcGFjaW5nPSIwcHgiPjxtdHI+PG10ZD48bW4+MjwvbW4+PG1pIG1hdGh2YXJpYW50PSJub3JtYWwiPmI8L21pPjwvbXRkPjxtdGQ+PG1vPj08L21vPjwvbXRkPjxtdGQ+PG1uPjU8L21uPjxtaSBtYXRodmFyaWFudD0ibm9ybWFsIj5jPC9taT48L210ZD48L210cj48bXRyPjxtdGQ+PG1uPjI8L21uPjxtaSBtYXRodmFyaWFudD0ibm9ybWFsIj5iPC9taT48L210ZD48bXRkPjxtbz49PC9tbz48L210ZD48bXRkPjxtcm93Pjxtbj41PC9tbj48bW8+KDwvbW8+PG1uPjQ8L21uPjxtbz4pPC9tbz48L21yb3c+PC9tdGQ+PC9tdHI+PG10cj48bXRkPjxtaSBtYXRodmFyaWFudD0ibm9ybWFsIj5iPC9taT48L210ZD48bXRkPjxtbz49PC9tbz48L210ZD48bXRkPjxtZnJhYz48bW4+MjA8L21uPjxtbj4yPC9tbj48L21mcmFjPjwvbXRkPjwvbXRyPjxtdHI+PG10ZD48bWkgbWF0aHZhcmlhbnQ9Im5vcm1hbCI+YjwvbWk+PC9tdGQ+PG10ZD48bW8+PTwvbW8+PC9tdGQ+PG10ZD48bW4+MTA8L21uPjwvbXRkPjwvbXRyPjwvbXRhYmxlPjwvbWF0aD5Ko11fAAAAAElFTkSuQmCC)
4. Nilai koefiesien yang telah diperoleh disubtitusikan ke persamaan reaksi kimia
![Error converting from MathML to accessible text.](data:image/png;base64,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)
5. Pemeriksaan jumlah atom di ruas kiri dan kanan
![](https://imgix2.ruangguru.com/assets/miscellaneous/jpg_1iam85_7954.JPG)
Tabel diatas menunjukkan bahwa jumlah atom diruas kiri dan kanan sudah setara, sehingga persamaan reaksi sudah setara.
Jadi, persamaan reaksi yang sudah setara adalah sebagai berikut:
![begin mathsize 14px style P subscript bold 4 bold and bold 10 Cl subscript bold 2 bold yields bold 4 P Cl subscript bold 5 end style](data:image/png;base64,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)