$\text{ For the reaction, }\mathrm{x}+2\mathrm{y}⟶\mathrm{z}$

5 moles of x and 9 moles of y will produce

In a chemical reaction, coefficient represents mole of that substance,

$\mathrm{x}+2\mathrm{y}⟶\mathrm{z}$

This indicates I mole of xreacts with 2 moles of y to form I mole of z.

So, 5 moles of x will require l0 moles of y. but we have taken only 9 moles of y.

Hence, y is limiting quantity, now we determine product from y.

Thus, 5 moles of x react with 9 moles of y to form 4.5 moles of z.