食醋中含有醋酸等有机酸及少量氨基酸。食醋的酸度是指每
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E)
食醋中含酸(均折合成醋酸计)的质量。国家标准规定酿造食醋酸度不得低于
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmrow%3E%3Cmrow%3E%3Cmtext%3Eg%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmo%3E%2F%3C%2Fmo%3E%3Cmrow%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmrow%3E%3C%2Fmrow%3E%3C%2Fmath%3E)
。可用滴定法测定食醋的酸度。某小组同学量取
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E)
自制食醋样品稀释至
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E)
(溶液几乎无色),每次量取
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmn%3E5%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E)
于锥形瓶中,加入
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E)
中性甲醛溶液(掩蔽氨基的碱性),以酚酞为指示剂,用
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E.%3C%2Fmn%3E%3Cmn%3E1%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmn%3E0%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3Eo%3C%2Fmtext%3E%3Cmtext%3El%3C%2Fmtext%3E%3Cmo%3E%E2%8B%85%3C%2Fmo%3E%3Cmsup%3E%3Cmrow%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmrow%3E%3Cmrow%3E%3Cmo%3E%E2%88%92%3C%2Fmo%3E%3Cmn%3E1%3C%2Fmn%3E%3C%2Fmrow%3E%3C%2Fmsup%3E%3Cmtext%3E+%3C%2Fmtext%3E%3Cmtext%3EN%3C%2Fmtext%3E%3Cmtext%3Ea%3C%2Fmtext%3E%3Cmtext%3EO%3C%2Fmtext%3E%3Cmtext%3EH%3C%2Fmtext%3E%3C%2Fmath%3E)
标准溶液滴定,滴定管读数记录如下表。
溶液的体积
| 第一次 | 第二次 | 第三次 |
滴定前 溶液的体积读数![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E%2F%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E) | 0.00 | 1.00 | 2.00 |
滴定后 溶液的体积读数![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmn%3E%2F%3C%2Fmn%3E%3Cmtext%3Em%3C%2Fmtext%3E%3Cmtext%3EL%3C%2Fmtext%3E%3C%2Fmath%3E) | 9.90 | 11.00 | 12.10 |
下列说法错误的是
- A、醋酸易溶于水与“醋酸分子和水分子之间能形成氢键”有关
- B、锥形瓶中溶液由无色变为粉红色,且半分钟内不褪色时停止滴定
- C、该自制食醋样品的酸度不符合国家标准
- D、若不加甲醛溶液,测定结果会偏低