Preparation and calibration:

一、配制：將氫氧化鈉配成飽和溶液，注進(jìn)塑料桶中密閉放置溶液清亮，使用前以塑料管虹吸上層清液。濃度氫氧化鈉飽和溶液注進(jìn)不含CO2的水0.1mol/L量取5ml1000中搖勻0.2mol/L量取10ml1000中搖勻0.5mol/L量取26ml1000中搖勻1.0mol/L量取52ml1000中搖勻

1、 Preparation: prepare sodium hydroxide into a saturated solution, inject it into a plastic bucket and place it tightly until the solution is clear. Siphon the supernatant with a plastic pipe before use. Inject 0.1mol/l of CO2 free water into the saturated solution of sodium hydroxide, take 5ml of 1000, shake well, take 0.2mol/l of 10ml of 1000, take 26ml of 1000, shake well, take 1.0mol/l of 52ml of 1000, shake well

二、標(biāo)定：

2、 Calibration:

1、原理：KHC8H4O4＋NOH→KNaC8H4O4＋H2O酸式酚酞堿式酚酞HIn→In-+H+（無(wú)色）（紅色）酚酞為一有機(jī)弱酸，在酸性溶液中為無(wú)色，當(dāng)堿色離子增加到一定濃度時(shí)，溶液即呈粉紅色。

1. Principle: khc8h4o4 + Noh → knac8h4o4 + H2O acid phenolphthalein basic phenolphthalein Hin → in - + H + (colorless) (red) phenolphthalein is an organic weak acid and colorless in acidic solution. When the alkali ion increases to a certain concentration, the solution will turn pink.

2、儀器：滴定管50ml；三角瓶250ml。

2. Instrument: burette 50ml; Triangular flask 250ml.

3、標(biāo)定過(guò)程0.1mol/LNOH標(biāo)準(zhǔn)溶液稱取0.4－0.6克；0.2mol/L稱1－1.2克；0.5mol/L稱取3克于105－110℃烘恒重的苯二甲酸氫鉀，稱準(zhǔn)0.0002克，分別溶于50ml；80ml不含二氧化碳水中,加2滴1％酚酞指示劑，用配好的待標(biāo)定溶液溶液呈粉紅色與標(biāo)準(zhǔn)色相同。同時(shí)作空缺試驗(yàn)。

3. Weigh 0.4-0.6g of 0.1mol/lnoh standard solution during calibration; 0.2mol/l weighs 1-1.2g; 0.5mol/l weigh 3 g of potassium hydrogen phthalate baked to constant weight at 105-110 ℃, weigh to 0.0002 g, and dissolve in 50ml respectively; 80ml carbon dioxide free water, add 2 drops of 1% phenolphthalein indicator, and use the prepared solution to be calibrated until the solution is pink and the same as the standard color. At the same time, the vacancy test is carried out.

4、計(jì)算：C（NaOH）=m/(V1-V2)*0.2042C（NaOH）---氫氧化鈉溶液濃度m——苯二甲酸氫鉀之質(zhì)量（克）V1——氫氧化鈉溶液用量（毫升）V2——空缺氫氧化鈉溶液用量（毫升）0.2042——與1.000mol/LNOH標(biāo)準(zhǔn)溶相當(dāng)?shù)囊钥吮硎敬_當(dāng)量苯二甲酸氫鉀之質(zhì)量

4. Calculation: C (NaOH) = m / (V1-V2) * 0.2042c (NaOH) -- concentration of sodium hydroxide solution m -- mass of potassium hydrogen phthalate (g) V1 -- dosage of sodium hydroxide solution (ML) V2 -- dosage of vacant sodium hydroxide solution (ML) 0.2042 -- mass of potassium hydrogen phthalate equivalent to 1.000mol/lnoh standard solution expressed in grams

5、留意事項(xiàng)：

5. Precautions:

1、為使標(biāo)定的濃度正確，標(biāo)定后應(yīng)用相應(yīng)濃度鹽酸對(duì)標(biāo)。

1. In order to make the calibrated concentration correct, the corresponding concentration of hydrochloric acid shall be used for benchmarking after calibration.

2、液溶有效期2個(gè)月。

2. The validity period of liquid solution is 2 months.

3、氫氧化鈉飽和溶液之配制：于1000硬質(zhì)容器中，加70毫升水，逐漸加進(jìn)700克氫氧化鈉。隨加隨攪拌，使溶解完全冷卻后移進(jìn)盛氫氧化鈉飽和液之試瓶中，以膠塞密塞，靜置7天以上，使含之碳酸鈉沉淀完全。取澄清之氫氧化鈉飽和液少許，加水稀釋，加氫氧化鋇飽和液1毫升，十分鐘內(nèi)不產(chǎn)生渾濁，表示碳酸鈉已沉淀完全。濃度：氫氧化鈉溶解度111g/100ml(20°C)

3. Preparation of saturated sodium hydroxide solution: add 70 ml of water to 1000 hard containers and gradually add 700 g of sodium hydroxide. Stir as you add it to make it dissolve completely, cool it, transfer it to the test bottle containing sodium hydroxide saturated solution, plug it with glue, and let it stand for more than 7 days to make the sodium carbonate precipitate completely. Take a little clarified sodium hydroxide saturated solution, dilute it with water, add 1ml barium hydroxide saturated solution, and there is no turbidity within ten minutes, indicating that sodium carbonate has been completely precipitated. Concentration: sodium hydroxide solubility 111g / 100ml (20 ° C)

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