【Daily Question】November 12, 2015: Participation +2 Wealth； +3 to 8 wealth for correct answers
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This post was last edited by zjp on 2015-11-14 at 10:02. To increase the popularity of the chemical analysis section, a \"One Question per Day\" campaign has been launched; this aims to foster active technical exchanges while also providing financial rewards to users. 【Daily Question】 (Single-choice question) A basic solution is a mixture of NaOH and Na2CO3. It is titrated with a standard HCl solution; first, using phenolphthalein as an indicator, V1 mL of HCl solution is consumed, and then, using methyl orange as an indicator, another V2 mL of HCl solution is used. The relationship between V1 and V2 is ( ). A Vl=V2 B Vl=2V2 C Vl＞V2 D Vl ＜V2 Please reply with your answer; answering the question earns +2 wealth points. Those who get all answers correct will receive an additional +3 to +8 wealth points. Extra rewards will be given for thorough analyses and explanations of the questions or answers, or for detailed calculation processes. If your answer is correct and your analysis is accurate, it will be marked as the best reply (or the best assistance). Feel free to answer the questions. Note: We will close this post after 24 hours, and at that time we will announce the best reply (the best assistance), as well as the answer and explanation.
C, V1 > V2-------------------------------------------------
A certain alkaline solution is a mixture of NaOH and Na2CO3. It is titrated with a standard HCl solution; first, using phenolphthalein as an indicator, V1 mL of HCl solution is consumed, and then, using methyl orange as an indicator, another V2 mL of HCl solution is used. The relationship between V1 and V2 is (C, V1 > V2).
A certain alkaline solution is a mixture of NaOH and Na2CO3. It is titrated with a standard HCl solution; first, using phenolphthalein as an indicator, V1 mL of HCl solution is consumed, and then, using methyl orange as an indicator, another V2 mL of HCl solution is used. The relationship between V1 and V2 is (C)
It should be C; sodium carbonate will gradually bind hydrogen ions
A certain alkaline solution is a mixture of NaOH and Na2CO3. It is titrated with a standard HCl solution; first, using phenolphthalein as an indicator, V1 mL of HCl solution is consumed, and then, using methyl orange as an indicator, another V2 mL of HCl solution is used. The relationship between V1 and V2 is (C). A Vl=V2 B Vl=2V2 C Vl＞V2 D Vl ＜V2
In the first step, using phenolphthalein as an indicator, sodium hydroxide is titrated to sodium chloride, and sodium carbonate is titrated to sodium bicarbonate; the volume V1 consumed is proportional to the sum of their amounts in moles. In the second step, using methyl orange as an indicator, sodium bicarbonate is titrated to sodium chloride, and the volume V2 consumed is proportional to the amount of sodium bicarbonate (sodium carbonate) in moles. Therefore, V1 > V2; the answer is C
C Vl＞V2 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!