Question

Examine the equation. C3H8 + 5O2 → 3CO2 + __H2O In order to balance the equation, what coefficient must be placed in front of H2O?
A.8
B.4
C.3
D.1

Answer 1

Answer : The correct option is, (B) 4

Explanation :

Balanced chemical reaction : It is a chemical reaction in which the number of individual atoms of an element in reactant side always be equal to the number of individual atoms of an element in product side.

The unbalanced chemical reaction is,

$C_3H_8+5O_2\rightarrow 3CO_2+H_2O$

The given reaction is an unbalanced reaction because in this reaction number of oxygen and hydrogen atoms are not balanced.

In order to balance the chemical reaction, the coefficient 4 is put before the $H_2O$.

The given balanced reaction will be,

$C_3H_8+5O_2\rightarrow 3CO_2+4H_2O$

Therefore, the coefficient must be placed in front of $H_2O$ is, 4

Answer 2

There are 8 hydrogen on the left, so there must be 8 hydrogen on the righ.
>>> 4H2O <<<<

.............
B. 4