Which of the following reactions will result in a reduced total pressure?

Question

a.
CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
c.
2HI(g) → H2(g) + I2(g)
b.
2N2O(g) → 2N2(g) + O2(g)
d.
2H2(g) + O2(g) → 2H2O()

Answer 1

The one with the smaller moles of gas on the right. You didn't finish d. Is that H2O(l) or H2O(g). However, that change will not affect the answer.