Given the balanced equation:
2c + 3h2==> c2h6
what is the total number of moles of c that must completely react to produce 2.0 moles of c2h6?
(1) 1.0 mol (3) 3.0 mol
(2) 2.0 mol (4) 4.0 mol

The correct answer is option 4.

Explanation:

According to the reaction, 1 mol of is obtained from 2 moles of C gives

Then, 2 moles of will be obtained from:

moles of C =4 moles

Hence, the correct answer is option 4.