C2H2 + O2 - CO2 + H20
What coefficients are required to correctly balance

The answer to your question is 2, 5, 4, 2

Explanation:

Data

Unbalanced chemical reaction

                 C₂H₂  +  O₂  ⇒   CO₂  +  H₂O

          Reactants     Elements      Products

                2              Carbon               1

                2              Hydrogen           2

                2              Oxygen              3

Balanced chemical reaction

                 2C₂H₂  +  5O₂  ⇒   4CO₂  +  2H₂O

          Reactants     Elements      Products

                4              Carbon               4

                4              Hydrogen           4

               10              Oxygen              10

The coefficients of the balanced equations are  2, 5, 4, 2

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2

a). in this case, dh> 0 and sd> 0. if t becomes larger, the term "-tds" will become more negative. at some point, it is possible that -dts will be more negative than the dh is positive, and the reaction will become spontaneous. this is probably the correct answer, but you should look at all of the other possibilities and make sure of that.