Answer:
The correct option is (a).
Explanation:
We need to find the product of given numbers.
First number = 29.5
Second number = 240
Product of two numbers = 29.5 × 240
= 
Zeroes from numerator and denominator get cancelled.
So,

Hence, the correct option is (a).
The balanced reaction is
Na2O + H2O --> 2NaOH
If 2.24 moles of sodium oxide react, that means 4.48 moles of NaOH is formed as it is a 1 to 2 stoichiometric relationship.
Now we multiply by the molar mass to get grams.
4.48 moles NaOH * (39.997 grams/1 mole) = 179.2 grams
Your answer is 179. grams.
When placed in a container, the heaviest (most dense) will sink to the bottom and the lightest (least dense) will rise to the top.
Therefore, Gasoline would rise to the top.