Question

Hydrogen and carbon dioxide are gases. If they are formed in the reaction you will see bubble. This can be a sign that a chemical reaction has happened.
 Write a balanced chemical reaction between hydrogen and carbon dioxide gas.
(A) $C{{O}_{2}}(g)+{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$
(B) $7CO{}_{2}(g)+{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$
(C) $C{{O}_{2}}(g)+3{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$
(D) $C{{O}_{2}}(g)+2{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$

Answer 1

Hint: Both carbon dioxide and hydrogen gas are colourless gases. When carbon dioxide and hydrogen gas react with each other, they liberate carbon monoxide and water as products. A balanced chemical reaction is a reaction that has equal number of atoms present of each element in the reactants in the left hand side and in the products in the right hand side.

Complete step by step answer:
A. $C{{O}_{2}}(g)+{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$

In this chemical equation, there is one carbon atom on each side, two oxygen atoms, and two atoms of hydrogen on both the sides of the reaction. Hence, it is a balanced chemical reaction between carbon dioxide and hydrogen. But let us see the other options as well.

B. $7CO{}_{2}(g)+{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$

In this chemical equation, there are seven carbon atoms on the left hand side and one carbon atom on
right hand side, fourteen oxygen atoms on the reactants side and two oxygen atoms on products side, and two atoms of hydrogen on both the sides of the reaction. Therefore, the chemical reaction is not balanced.

C. $C{{O}_{2}}(g)+3{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$

In the above chemical equation, there is one carbon atom on left hand side and right hand side, two oxygen atoms on both the sides, but six atoms of hydrogen on reactants side and two atoms of hydrogen on products side in the reaction. Therefore, this chemical reaction is also not balanced.

D. $C{{O}_{2}}(g)+2{{H}_{2}}(g)\to CO(g)+{{H}_{2}}O(g)$

In the above chemical equation, there is one carbon atom on the left hand side and right hand side of the reaction, again two oxygen atoms on both the sides, but four atoms of hydrogen on reactants side and two atoms of hydrogen on products side in the reaction. Therefore, this chemical reaction is also not balanced.

So, the correct answer is Option A.

Note: The reaction between carbon dioxide and hydrogen gas is an endothermic reaction, that means, it requires heat for the reaction to occur.

$C{{O}_{2}}(g)+{{H}_{2}}(g)+41.2kJ\to CO(g)+{{H}_{2}}O(g)$

The enthalpy change for the given reaction represents the heat of reaction. The reaction between carbon dioxide and hydrogen gas is reversible in nature.