Answer:
100 g of water has the highest number of moles
Explanation:
Recall that the number of moles is obtained as given mass/formula weight
For HCl;
number of moles = 100g/36.5g/mol = 2.7 moles
For H2O;
number of moles = 100g/18g/mol = 5.5 moles
For MgCO3
number of moles = 100g/84.3 g/mol = 1.2 moles
For AlCl3
number of moles = 100g/133.3g/mol = 0.75 moles
For NaCl
number of moles = 100g/58.4 g/mol = 1.7 moles
Answer:- 10 L of ethane.
Solution:- The given balanced equation is:

From this equation, ethane and oxygen react in 2:7 mol ratio, the ratio of volumes would also be same if they are at same temperature and pressure.
Since 14 L of each gas are taken, the oxygen will be the limiting reactant and ethane will be the excess reactant. Let's calculate the volume of ethane used:

= 
From above calculations, 4 L of ethane are used. So, excess volume of ethane left after the completion of reaction = 14 L - 4 L = 10 L
Hence, 10 L of ethane will be remaining.
The answer is gas only.
hope this helps!