1. Questions

Chem

Compound A is a clear colorless liquid with a familiar, pleasant odor, which boils at 91-92C. A dissolves readily in water. When a solution of 5 drops of A in 1 mL of water is tested with blue and red litmus, neither test paper is seen to change color.

The addition of a few drops of chromic acid reagent to A produces a distinct blue-green color. Heat is evolved.

When A is mixed with water and sodium hydroxide solution, then treated with several drops of solution of I2 in aquous KI, a bulky yellow precipatate is formed. The ppt. is collected, washed with water and dried. It melts at 118-122C.

A is mixed with an equal volume of 3,5-dinitrobenzoyl chloride and heated briefly. After cooling, some 5% aqueous NaHCO3 solution is added to the reaction, and a ppt. forms. collection, wahsing of the ppt. and recrystallization from ethanol/water results in colorless crystals that melt at 75-74C

~ Identify A and describe an appropriate derivative

~ Provide equations for all reactions described.

Please help.


Jay,
I'm not an organic chemist so you should confirm the following.
The boiling point has given me trouble and I may not have identified the material correctly but I can give some tips on how to make sure. First, the KI-I2 test is the classic iodoform test. The yellow bulky pptd material is CHI3, iodoform. The meltint point for iodoform, according to the Merck Index is 122. The iodoform test is a test primarily for aldehydes, ketones, and alcohols. The chromic acid simply oxidizes the material. Isopropyl methyl ketone is the only ketone listed in my tables even close (94 degrees) to the boiling point of the compound (91-92 degrees) and I don't know that it would react with 3,5-dinitrobenzoyl chloride. The only aldehyde listed is isovaleraldehyde (92 degrees C). which according to The Merck Index, has a pungent odor which violates the first part of the statement AND I don't know that it will react with 3,5-dinitrobenzoyl chloride. That leaves us with alcohols for they can be oxidized to produce the characteristic iodoform test. There is an alcohol, n-propyl alcohol, which has a boiling point of 97 degrees C (too high according to the above), AND it produces a 3,5-dinitrobenoate that melts at 74 degrees and that agrees with the statement. I don't know if this is an unknown in the lab or a problem you have been given. If a lab unknown, perhaps the boiling point above is a typo OR perhaps you measured the boiling point incorrectly OR perhaps it was a slightly impure sample. No matter which case we have, the proper thing to do is to make the alpha-naphthylurethan (melting point of 80 C) or the phenylurethan (melting point of 51 C)(which also answers the last part of the statement). That will tell you if you are on the wrong track or the right track. I hope this helps.

  1. 👍
  2. 👎
  3. 👁
Jay

Respond to this Question

First Name

Your Response

Similar Questions

  1. Chemistry

    While heating two different samples of water at sea level, one boils at 102°C and one boils at 99.2°C. Calculate the percent error for each sample from the theoretical 100.0°C.

  2. chemistry

    Methanol, CH3OH, a colorless, volatile liquid, was formerly known as wood alcohol. It boils at 65.0°C and has a heat of vaporization of 37.4 kJ/mol. What is its vapor pressure at 22.0°C?

  3. science

    A drinking glass at a crime scene contains a clear colorless liquid that may be water or alcohol. As the investigator, you know that the densities of alcohol, water, and ice are 0.79g/mL, and 0.92/mL. Design a simple method to

  4. Science

    Physical properties used to indicate temperature changes include all of the following except a. color changes of liquid crystals b. volume changes of fluids and solids c. changes in electrical resistance d. odor changes in solids

  1. Chem

    1.10g of an unknown compound reduces the freezing point of 75.22g benzene from 5.53C to 4.92C. What is the molar mass of the compound?

  2. Science Help!

    A student mixed two clear liquids together in a beaker. A solid and a new liquid formed. The student forgot to write down the mass of one of the reactansts. The rest of the data are shown in the table below. Table Mass (g) Liquid

  3. Chemistry

    Identify which of the following changes is exothermic. a) liquid water boils to steam b) liquid water freezes to give ice c) ice melts to give liquid water d) liquid water increases in temperature from 35 C to 45 C

  4. Science

    Water and gasoline are both clear liquids at room temperature. Describe one physical property and one chemical property that might be used to distinguish between them. Plz help physical:smell chemical: pH value What about density?

  1. Chemistry

    Which of the changes are chemical changes? a) Sugar crystals are ground to a fine powder. b) A candle is burned c) Two clear colorless salt solutions are mixed and a bright orange precipitate forms. d) Candle wax is melted e) A

  2. Chemistry

    Isopropyl alcohol, C3H7OH is an organic compound. It melts at -89 C and boils at 82.6 C. IT has a heat fusion of 88 J/g and a heat of vaporization of 733.33 J/g. The specific heat of liquid isopropyl alcohol is 2.68 J/g-C. The

  3. Chemistry

    A) A compound distributes between water (solvent 1) and benzene (solvent 2) with Kp = 2.7. If 1.0g of the compound were dissolved in 100mL of water, how much compound could be extracted by three 10-mL portions of benzene? B) If

  4. Chemistry

    During recrystallization, an orange solution of a compound in hot alcohol was treated with activated carbon and then filtered through fluted paper. On cooling, the filtrate gave gray crystals, although the compound was reported to

You can view more similar questions or ask a new question.