Question

When two intermediate chemical equations are combined, the same substance that appears in the same phase can be canceled out, provided that
A) it is a reactant in one intermediate reaction and a catalyst in the other reaction.
B) it is a product in one intermediate reaction and a catalyst in the other reaction.
C) it is a reactant in one intermediate reaction and a product in the other reaction.
D) it is a reactant in both of the intermediate reactions.

Answer 1

The right answer for the question that is being asked and shown above is that: "C) it is a reactant in one intermediate reaction and a product in the other reaction." When two intermediate chemical equations are combined, the same substance that appears in the same phase can be canceled out, provided that it is a reactant in one intermediate reaction and a product in the other reaction.

Answer 2

Answer: Option (C) is the correct option.

Explanation:

When two intermediate chemical equations are combined, the same substance that appears in the same phase can be canceled out, provided that   it is a reactant in one intermediate reaction and a product in the other reaction.

For example,

$2Al(s) + 2KOH(aq) + 6H_{2}O\rightarrow 2KAl(OH)_{4}(aq)+ 3H_{2}(g)$ ....(1)

$2KAl(OH)_{4}(aq) + 4H_{2}SO_{4}(aq) + 6H_{2}O(l)\rightarrow 2KAl(SO_{4})_{2}(aq)+ 12H_{2}O(s)$  .........(2)

Cancelling the common species in both the equations as follows.

$2Al(s) + 2KOH(aq) + 6H_{2}O\rightarrow \not{2KAl(OH)_{4}(aq)}+ 3H_{2}(g)$

$\not{2KAl(OH)_{4}(aq)}+ 4H_{2}SO_{4}(aq) + 6H_{2}O(l)\rightarrow 2KAl(SO_{4})_{2}(aq)+ 12H_{2}O(s)$

Therefore, on addition we get the equation as follows.

$2Al(s)+ 2KOH(aq) + 4H_{2}SO_{4}(aq) + 22H_{2}O(l)\rightarrow 3H_{2}(g)+ 2KAl(SO_{4})_{2} + 12H_{2}O(s)$