$\_\_\_\_$ grams of 3-Hydroxy propanal (MW=74) must be dehydrated to produce 7.8 g of acrolein $(\mathrm{MW}=56)\left(\mathrm{C}_3 \mathrm{H}_4 \mathrm{O}\right)$ if the percentage yield is 64 .
(Round off to the Nearest Integer).
[Given : Atomic masses : C : $12.0 \mathrm{u}, \mathrm{H}: 1.0 \mathrm{u}$, $\mathrm{O}: 16.0 \mathrm{ul}$