In chemistry, there is a common note that says, "Like dissolves like".
This pertains to the concept that polar substances can dissolve only other polar substances. Also, nonpolar substances are also only able to dissolve nonpolar substances.
Polarity of the substance depends primarily on the type of bond and the difference in electronegativity.
Water is a polar substance while vegetable oil is not. From the concept presented above, it may be concluded that water will not be able to dissolve the vegetable oil and the assumption is logical.
Answer :
(a) The number of moles of D produced can be, 6.67 moles.
(b) The volume of D prepared can be, 24.5 L
Explanation :
The given chemical reaction is:

Part (a) :
From the balanced chemical reaction, we conclude that:
As, 3 moles of A react to give 5 moles of D
So, 4 moles of A react to give
moles of D
Thus, the number of moles of D produced can be, 6.67 moles.
Part (b) :
As we know that 1 moles of substance occupies 22.4 L volume of gas.
As,
volume of B gives
volume of D
As, 9.8 L volume of B gives
volume of D
Thus, the volume of D prepared can be, 24.5 L
Lead is an E (element) and can be found on the periodic table.