For the reaction, CO(g) + 1/2 O2(g) → CO2(g) which of the following is correct?

Question

For the reaction, CO(g) + \(\frac12\)O₂(g) → CO₂(g) which of the following is correct?

(A) ΔΗ - ΔΕ

(B) ΔΗ < ΔΕ

(C) ΔΗ > ΔΕ

(D) None of these

Answer 1

Correct option is (B) ΔΗ < ΔΕ

Since, ΔU = nRΔT

So, at constant temperature ΔT = 0

⇒ ΔU = 0

Also, ΔH = ΔU + (Δn_g)RT, where Δn_g = change in gaseous moles

Since, Δn_g = 1 − 1 − 0.5 = −0.5

So, ΔH = 0 + (−0.5)RT = −0.5RT < 0

Hence, ΔH < ΔU

i.e., ΔH < ΔE