次氯酸钠，化学式NaClO，是钠的次氯酸盐。次氯酸钠与二氧化碳反应产生的次氯酸是漂白剂的有效成分。

氯气溶于冷而且稀的氢氧化钠溶液产生次氯酸钠、氯化钠及水：

Cl₂ + 2NaOH → NaClO + NaCl + H₂O

注意氯气溶于热而且浓的氢氧化钠溶液不会产生次氯酸钠，而会生成氯化钠、氯酸钠及水：

3Cl₂ + 6NaOH → 5NaCl + NaClO₃ +3H₂O

Sodium hypochlorite is a chemical compound with the formula NaOCl. It is composed of a sodium cation (Na+) and a hypochlorite anion (ClO−); it may also be viewed as the sodium salt of hypochlorous acid. When dissolved in water it is commonly known as bleach, or liquid bleach. Sodium hypochlorite is practically and chemically distinct from chlorine. Sodium hypochlorite is frequently used as a disinfectant or a bleaching agent.