Hypobromous acid (English spelling)

One of the oxoacids of bromine. It exists only as an aqueous solution. It is a very weak monobasic acid. Its chemical formula is HBrO and its formula weight is 96.9. As a hydrolysis product of bromine, it exists in trace amounts in aqueous bromine solutions, maintaining the following equilibrium. Its concentration in saturated bromine water at 25°C is 0.00192 mol/L. It is a yellow solution with a peculiar odor.

_Br2 + _H2OHBrO + HBr
The degree of hydrolysis is much less than that with chlorine, but is complete in the presence of silver ions. It is obtained by distilling the reaction solution of silver nitrate and bromine water under reduced pressure. In alkaline solution, hypobromite is stable only near 0°C, and at high temperatures it disproportionates to bromide and bromate. It is a strong oxidizing agent.

[Kenichi Morinaga and Katsunori Nakahara]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

臭素のオキソ酸の一つ。水溶液としてのみ存在する。きわめて弱い一塩基酸。化学式HBrO、式量96.9。臭素の加水分解生成物として、臭素水溶液中に次の平衡を保って微量に存在する。25℃の飽和臭素水中の濃度は0.00192mol/L。黄色特異臭のある溶液。

　　Br₂＋H₂OHBrO＋HBr
加水分解の程度は塩素の場合よりもずっと小さいが、銀イオンがあると完全に進む。硝酸銀水溶液と臭素水の反応溶液を減圧蒸留して得られる。アルカリ性溶液で次亜臭素酸塩は0℃付近でのみ安定で、高温で臭化物と臭素酸塩に不均化する。強い酸化剤。

［守永健一・中原勝儼］

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