Question

For the reaction \[\ce{N2 + 3H2 ⇌ 2NH3}\]; if `(∆["NH"_3])/(∆"t")` = 2 × 10⁻⁴ mol dm⁻³ s⁻¹, the value of `(-Δ["N"_2])/(∆"t")` would be ____________.

Options

• 1 × 10⁻⁴ mol dm⁻³ s⁻¹

• 3 × 10⁻⁴ mol dm⁻³ s⁻¹

• 4 × 10⁻⁴ mol dm⁻³ s⁻¹

• 6 × 10⁻⁴ mol dm⁻³ s⁻¹

Answer 1

For the reaction \[\ce{N2 + 3H2 ⇌ 2NH3}\]; if `(∆["NH"_3])/(∆"t")` = 2 × 10⁻⁴ mol dm⁻³ s⁻¹, the value of `(-Δ["N"_2])/(∆"t")` would be 1 × 10⁻⁴ mol dm⁻³ s⁻¹.

Explanation:

\[\ce{N2 + 3H2 ⇌ 2NH3}\]

The average rate of reaction

`(-Δ["N"_2])/(∆"t") = -1/3 (Δ["H"_2])/(Δ"t") = 1/2 (Δ["NH"_3])/(Δ"t")`

∴ `(-Δ["N"_2])/(∆"t") = 1/2 xx (Δ["NH"_3])/(Δ"t") = (2 xx 10^-4)/2`

= 1 × 10⁻⁴ mol dm⁻³ s⁻¹