Question

All of the following are empirical formulas EXCEPT? 1 Al₃(SO₄)₂, 2 NaOH, 3 N₂O₄, 4 C₃H₈.

Answer 1

Answer:

3N2O4

Explanation:

all other are empirical formula except one which is N2O4

Answer 2

The correct option is 1.

• Al exists as $Al^{+3}$ ion and the anion exist as $SO_4^{2-}$ ion. Thus according to the criss-cross method, its molecular formula should be $Al_2(SO_4)_3$.
• Na exists as $Na^+$ ion and the anion exist as $OH^-$ ion. Thus according to the criss-cross method, its molecular formula is NaOH.
• $N_2O_4$ is an oxide of nitrogen.
• $C_3H_8$ is the formula of an alkane.