The equilibrium: H₂(g) + I₂(g) ⇌ 2HI(g) has equal moles of gas on both sides. What happens to the equilibrium position when the pressure is doubled?

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Question

The equilibrium: H₂(g) + I₂(g) ⇌ 2HI(g) has equal moles of gas on both sides. What happens to the equilibrium position when the pressure is doubled?

Accepted Answer

It remains unchanged because moles of gas are equal on both sides — When the number of moles of gas is the same on both sides of the equation (2 moles on each side), changing pressure has no effect on the equilibrium position. The system cannot shift to reduce or increase the number of gas molecules because both sides are equal. This is an important special case students must recognise.

Answer

It shifts to the left, producing more H₂ and I₂

Answer

It shifts to the right, producing more HI

Answer

It shifts to the right because HI has a lower molar mass

Answer

It remains unchanged because moles of gas are equal on both sides

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