Question

27 g $Al$ will react completely with ________ g of oxygen to give Al${}_2$O${}_3$.

[Atomic mass of Al = 27]

• A. 24 g
• B. 8 g
• C. 40 g
• D. 10 g

Answer 1

The correct option is A 24 g

$2Al+\frac{3}{2}{O}_2⟶A{l}_2{O}_3$

Moles of $Al=\frac{27}{27}=1$ $mol$

$2$ $mole$ $Al$ gives $\frac{3}{2}$ $mole$ $O_2$

$1$ $mole$ $Al$ gives $\frac{3}{4}$ $mole$ $O_2$

Mass of oxygen $=\frac{3}{4}\times 32=24$ $gram$

Hence, the correct option ios $\left(A\right)$