<u>Answer:</u> The amount of water produced in the given reaction is
grams.
<u>Explanation:</u>
Let us assume that the initial amount of acetylene gas given be 'x' grams. Now, to calculate the number of moles, we will use the formula:
....(1)
Given mass of acetylene = x grams
Molar mass of acetylene = 26 g/mol
Putting values in above equation, we get:

The reaction of combustion of acetylene is given by the equation:

By Stoichiometry of the reaction:
2 moles of acetylene produces 2 moles of water.
So,
moles of acetylene will produce =
moles of water.
Now, to calculate the amount of water produced, we use equation 1:
Molar mass of water = 18 g/mol
Moles of water = 
Putting values in equation 1, we get:

grams