$$A(g) \rightleftharpoons 2B(g) + C(g)$$
For the given reaction, if the initial pressure is 450 mmHg and the pressure at time t is 720 mmHg at a constant temperature T and constant volume V. The fraction of A(g) decomposed under these conditions is $$x \times 10^{-1}$$. The value of x is (nearest integer) _______

We are given the reaction $$A(g) \rightleftharpoons 2B(g) + C(g)$$ with initial pressure 450 mmHg and total pressure at time $$t$$ equal to 720 mmHg. We need to find the fraction of A decomposed.

Let $$x$$ be the fraction of A that has decomposed. Initially, only A is present at 450 mmHg.

The stoichiometry tells us: for every mole of A that decomposes, 2 moles of B and 1 mole of C are formed.

The fraction of A decomposed is $$\frac{3}{10}$$. Expressed as a ratio, the numerator is 3.