Answer is: acid-base indicator or pH indicators.
Acid-base indicators are usually weak acids or bases and they are chemical<span> detectors for hydrogen or hydronium cations.</span>
Example for acid-base indicator is phenolphthalein (molecular formula C₂₀H₁₄O₄). Phenolphthalein is <span>colorless in </span>acidic<span> solutions and pink in </span>basic<span> solutions.
Another example is m</span><span>ethyl orange. It is red colour in acidic solutions and yellow colour in basic solutions.</span>
In the first distillation this week, Hexane from the original solvent makes a larger contribution to the vapor pressure of the mixture.
In between hexane and toluene, the hexane will have more vapor pressure contribution in the solution. The boiling point of hexane is much lower than toluene. Therefore, it will evaporate easily at low temperatures and start exerting pressure on the solution.
Hence between hexane and toluene, because of more vapor pressure of hexane and lower boiling point, it will easily evaporate and exerts pressure.
Therefore, from the original solvent, hexane makes a larger contribution to the vapor pressure of the mixture.
To learn more about vapor pressure and hexane, visit: brainly.com/question/28206662
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