Question

_________ grams of 3-Hydroxy propanal (MW=74) must be dehydrated to produce 7.8g of acrolein (MW=56) (\[{C_3}{H_4}O\]) if the percentage yield is 64. (Round off to the nearest integer).
[Given atomic masses; C=12.0 \[\mu \], H=1.0\[\mu \] , O=16.0\[\mu \]]

Answer 1

Hint: In the above-mentioned chemical reaction dehydration reaction is taking place. A dehydration reaction is a type of reaction in which there will be a loss of water from the chemical reaction. It is the reverse process of hydration reaction.

Complete Step by Step Solution:
When 3-Hydroxy propanal is dehydrated to produce 7.8g of acrolein, the chemical reaction is given as:


The moles of acrolein produced in the chemical reaction is:
\[\dfrac{{7.8}}{{56}} = 0.14\] moles
The percentage of yield would be equal to
\[\dfrac{{7.8/56}}{x} \times 100 = 64\]
\[x = \dfrac{{7.8 \times 100}}{{56 \times 64}} = \dfrac{{780}}{{56 \times 64}}\] moles
\[{W_{reac\tan t}} = \dfrac{{780}}{{56 \times 64}} \times 74 = 16.11\] grams

Therefore, 16.11 grams of 3-hydroxy propanal must be dehydrated to produce 7.8 grams of acrolein.

Note: Acrolein usually occurs as a colourless or yellow-colored liquid that dissolves in water very easily. It also has the tendency to quickly change into a vapour state when it is heated. Acrolein has a wide variety of uses such as in pesticides for controlling algae, weeds, bacteria, and mollusks. It also helps in the manufacturing of other industrial-based chemicals. It has a very choking odour and causes severe irritation to the eyes and mucous membrane. It is also toxic when it is inhaled and has a flash point which is below \[{0^o}F\]. It is less dense than water and its vapours are heavier than air. Very small amounts of acrolein can be produced and enter the atmosphere when oil. Plastics. Tobacco, gasoline, and oil are burned.