1Draw the structure of 2-methylpropan-2-ol
CH3-C(CH3)(OH)-CH3
2What safety precautions should be taken when chlorinating 2-methylpropan-2-ol using concentrated hydrochloric acid?
Wear safety goggles and gloves. Keep away from open flames as 2-methylpropan-2-ol and 2-chloro-2-methylpropane are flammable. Avoid skin contact with calcium chloride (irritant) and concentrated hydrochloric acid (corrosive). Perform the experiment in a fume cupboard due to toxic and corrosive HCl fumes.
3Write an equation for the reaction between 2-methylpropan-2-ol and hydrochloric acid
(CH3)3COH + HCl → (CH3)3CCl + H2O
4Why is anhydrous calcium chloride added to the mixture after the reaction is complete?
To ensure any unreacted alcohol remains in the lower aqueous layer rather than the organic layer containing the product.
5What is used to separate a mixture containing immiscible aqueous and organic substances?
Separating funnel
6Why is sodium hydrogencarbonate solution added to the organic mixture after the reaction is complete?
To remove any unreacted HCl.
7Write a balanced chemical equation for the reaction between hydrochloric acid and sodium hydrogencarbonate
HCl + NaHCO3 → NaCl + CO2 + H2O
8Why isn’t a strong base used to remove unreacted HCl when producing 2-chloro-2-methylpropane?
A strong base (e.g., NaOH) would react with the halogenoalkane product, causing hydrolysis and reforming the alcohol.
9Why is anhydrous sodium sulfate added to the organic layer after removing unreacted HCl?
To remove any traces of water from the mixture, as sodium sulfate acts as a drying agent.
10By what method can an impure liquid product be purified?
Distillation
11How can the purity of a substance be checked?
By measuring its melting or boiling point. A pure substance has a precise meltingoiling point, while an impure substance meltsoils over a larger temperature range.
12what is the method for chlorination of 2-methylpropan-2-ol (include steps)
1-Pour 10 cm³ of 2-methylpropane-2-ol and 35 cm³ of concentrated hydrochloric acid into a large conical flask and swirl.
2-Place the bung in the mouth of the flask and swirl again. Remove the bung to release the pressure.
3-Continue this for approximately 20 minutes until two layers begin to appear.
4-Add approximately 6 g of anhydrous calcium chloride and swirl until dissolved – this ensures all unreacted alcohol goes into the bottom aqueous layer and not the top organic layer.
5-Transfer the reaction to a separating funnel and allow it to settle into two layers. Run off and discard the lower layer, but keep the upper layer.
6-Add approximately 10 cm³ sodium hydrogencarbonate solution to the separating funnel, swirl while releasing the pressure. Run off and discard the lower aqueous layer, and repeat.
7-Run off the organic layer into a small conical flask and add a spatula of anhydrous sodium sulfate. Swirl and leave until the mixture appears completely clear (no cloudiness).
8-pour the organic liquid into a 50 cm³ pear-shaped flask and set up for distillation.
9-Collect the fraction boiling between 50 °C and 52 °C.
10- add excess nitric acid and a few drops of silver nitrate and record the observation