【Daily Question】November 8, 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 10:06. 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) In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL ； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, ( ) is present in the solution. A NaOH + Na2CO3 B Na2CO3 + NaHCO3 C NaHCO3 D Na2CO3 Please reply with your answer in the comments; answering correctly earns you +2 wealth points. Getting all answers right gives an additional +3 to +8 wealth points. Those who provide a thorough analysis and explanation of the questions or answers, or include detailed calculation processes, will receive extra wealth points as a reward. 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.
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, (B) is present in the solution.
B Na2CO3 + NaHCO3
There is ( ) in the solution: A NaOH + Na2CO3
B Na2CO3 + NaHCO3
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, the solution contains (B) Na2CO3 + NaHCO3.
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； With methyl orange as an indicator, further titration consumed 25.72 mL of the HCl standard solution; therefore, (b) is present in the solution. A NaOH + Na2CO3 B Na2CO3 + NaHCO3 C NaHCO3 D Na2CO3
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, (B) is present in the solution. A NaOH + Na2CO3 B Na2CO3 + NaHCO3 C NaHCO3 D Na2CO3
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, (B) is present in the solution. A NaOH + Na2CO3 B Na2CO3 + NaHCO3 C NaHCO3 D Na2CO3
In the double-indicator method for determining mixed bases, when phenolphthalein indicator is added, the volume of HCl standard titrant required is 15.20 mL； By adding methyl orange as an indicator and continuing the titration, an additional 25.72 mL of the HCl standard solution was consumed; therefore, (B) is present in the solution. A NaOH + Na2CO3 B Na2CO3 + NaHCO3 C NaHCO3 D Na2CO3