Question

part a
which of the following equations is not balanced properly?
4nh₃ + 14o₂ → 4no₂ + 6h₂o
2cr + 6hcl → 2crcl₃ + 3h₂
2nahco₃ → na₂co₃ + co₂ + h₂o
cr₂(so₄)₃ + 6koh → 2cr(oh)₃ + 3 k₂so₄
none of the above

Explanation:

Step1: Check first equation (N, H, O)

• N: Left = 4 ($4NH_3$), Right = 4 ($4NO_2$) ✔️
• H: Left = \(4\times3 = 12\) ($4NH_3$), Right = \(6\times2 = 12\) ($6H_2O$) ✔️
• O: Left = \(14\times2 = 28\), Right = \(4\times2 + 6\times1 = 8 + 6 = 14\) ❌ (28 ≠ 14)

Step2: Verify other equations (optional, but confirm)

• \(2Cr + 6HCl \to 2CrCl_3 + 3H_2\): Cr(2=2), H(6=6), Cl(6=6) ✔️
• \(2NaHCO_3 \to Na_2CO_3 + CO_2 + H_2O\): Na(2=2), C(2=2), H(2=2), O(6=6) ✔️
• \(Cr_2(SO_4)_3 + 6KOH \to 2Cr(OH)_3 + 3K_2SO_4\): Cr(2=2), S(3=3), K(6=6), O(18=18), H(6=6) ✔️

Answer:

\(4NH_3 + 14O_2 \to 4NO_2 + 6H_2O\) (the first equation is not balanced properly)