Question

Choose the incorrect formula out of the four compounds for an element X below :

• A. $X_2Cl_3$
• B. $X_2O_3$
• C. $X_2(SO_4)_3$
• D. $XPO_4$

Answer 1

Answer: (A)

$X_2Cl_3$

Answer 2

$X_{2}O_{3} \Rightarrow X^{3+}O^{2-}$
$X_{2}Cl_{3} \Rightarrow X^{3+}Cl^{2-}$
$X_{2}\left(SO_{4}\right)_{3} \Rightarrow X^{3+}SO_{4}^{2-}$
$XPO_{4} \Rightarrow X^{3+}PO_{4}^{3-}$
Because $Cl^{2-}$ does not exist. So, $X_{2}Cl_{3}$ is incorrect. The correct formula should be $XCl_{3}.$