Question

Experiment 6. the reduction of bencil (March 2020) Your name Sodium borohydride is a convert recent for the reduction of dehydes and ketones to 1" and 2 alcohols, respectively. The mechanism of the reaction (below) is straightforward and is driven by boron's affinity for oxygen. In addition, given borohydride's remarkably low reactivity with OH groups under neutral and especially basic conditions, this reaction can be done in alcohol solvents. This means that (unlike LAH or Grignard reactions) no separate hydrolysis step is required; boron very much wants a bond to oxygen, but is not particular about which Oxygen. So the excess of alcohol solvent (usually methanol) rapidly replaces the reduction product. In this experiment, we will be using borohydride to reduce the diketone known as benzil, followed by crystallization 212 AM For this experiment you will complete this worksheet in Word, and submit it to your TA by email Procedure: Weigh 500 mg record exact weight below) of benzill into a 50 mL Erlenmeyer flask, and add a medium size stir bar. Add 5 mL of ethanol. To the stirred suspension, add approx. 100 mg (record exact weight below) of sodium borohydride (weigh) and cap loosely with the small yellow cap provided (not airtight!). Exact amount of benzil used: 0.5849 Amount of ethanol used: 5.2mL Exact amount of sodium borohydride used: 0.1449 Observations: The Sun saution became warm and began as a murky yellow color, after the first few minutes OF Stirring the mixturé looked like an off White color. After Stirning For io minoresit loginesestio After stirring 10 minutes, 5 ml of water was added, then 10 mL of saturated aqueous sodium chloride solution. The flask was heated moderately on a stirring hotplate until the solid dissolved, then set aside to cool to room temperature Crystallization occurred water the Alteradding water the Amount of water used: 5.2 ml Solution 90oked like a Foggy 13 Amount of NaCl soln. used: 10 ml yellowish white. Addition of a saturated Nacl made the solution et look like a cloudy white color. As the solution ? to boil the white color rose to the top and be disappeared. Recrystallization Occured, crystalsgnite colore cooled, and the solution turned back into a Foggy white color. Ac. Ifter cooling in anice bath it looked like a give life white again plore

hello, i need help with the questions in the second photo

Answer 1