Question

consider the reaction
na + hcl → nacl + h₂
when balanced using the smallest possible
integer coefficients, what will be the sum of
the coefficients?
1 9
2 11
3 6
4 5
5 4
6 7
7 8
8 10

Explanation:

Step1: Balance H atoms

Original reaction: $\ce{Na + HCl -> NaCl + H_{2}}$. H on left: 1, right: 2. So put 2 before $\ce{HCl}$: $\ce{Na + 2HCl -> NaCl + H_{2}}$.

Step2: Balance Cl atoms

Cl on left: 2 (from $2\ce{HCl}$), right: 1 (from $\ce{NaCl}$). Put 2 before $\ce{NaCl}$: $\ce{Na + 2HCl -> 2NaCl + H_{2}}$.

Step3: Balance Na atoms

Na on left: 1, right: 2 (from $2\ce{NaCl}$). Put 2 before $\ce{Na}$: $\ce{2Na + 2HCl -> 2NaCl + H_{2}}$.

Step4: Sum coefficients

Coefficients: 2 (Na), 2 (HCl), 2 (NaCl), 1 (H₂). Sum: $2 + 2 + 2 + 1 = 7$.

Answer:

1. 7