Question

in the reaction ( 2h_{2}+o_{2}\to __h_{2}o ), what coefficient should be placed in front of ( h_{2}o ) to balance the reaction?

1

2

3

4

Explanation:

Step1: Count atoms on reactant side

• Hydrogen atoms: \(2\times2 = 4\) (from \(2H_2\))
• Oxygen atoms: \(2\) (from \(O_2\))

Step2: Balance hydrogen and oxygen atoms

• Let coefficient of \(H_2O\) be \(x\). For hydrogen: \(2x = 4\) (from reactant side hydrogen count), so \(x = 2\).
• For oxygen: In \(2H_2O\), oxygen atoms \(= 2\times1=2\) (matches reactant side oxygen count).

So coefficient of \(H_2O\) is \(2\).

Answer:

B. 2