When acetylene, C2H2, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO2 molecules and two H2O molecules.

Select the statement below that is incorrect in regard to this reaction.

A) if 12 CO2 molecules are formed, then six H2O molecules will also be formed.

B) if eight acetylene molecules react, 12 CO2 molecules will be formed.

C) the balanced equation for the reaction is 2C2H2 + 5O2 → 4CO2 + 2H2O.

D) If 12 H2O molecules are formed, then 30 O2 molecules must have reacted.

Option B. Is incorrect

Explanation:

The equation for the reaction is given below:

2C2H2 + 5O2 → 4CO2 + 2H2O

Now to know which option is wrong, let us examine the options to know which one is right.

For option A:

From the balanced equation above,

When 4 molecules of CO2 is produce, 2 molecules of H2O are also produce.

Therefore, when 12 molecules of CO2 are produced = (12x2) / 4 = 6 molecules of H2O are formed.

Therefore, option A is correct.

For option B:

From the balanced equation above,

2 molecules of C2H2 produced 4 molecules of CO2.

Therefore, 8 molecules C2H2 will produce = (8x4) / 2 = 16 molecules of CO2.

Option B is wrong as 16 molecules of CO2 are produced when 8 molecules of C2H2 reacted.

For option C.

The balanced equation for the reaction is

2C2H2 + 5O2 → 4CO2 + 2H2O

Option C is correct.

For option D.

From the balanced equation above, 5 molecules of O2 produced 2 molecules of H2O.

Therefore, X molecules of O2 will produce 12 molecules of H2O i. e

X molecules of O2 = (5x12) / 2

X molecules of O2 = 30 molecules

Option D is correct.

From the above illustrations, option B is wrong.