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

The Correct Option is A

To solve this question, we need to evaluate the given chemical formulas for element \( X \) and determine which one is incorrect based on standard chemical valencies and compound formation rules.

1. X_2Cl_3: Typically, chlorine has a valency of -1. However, for this compound to be valid, element \( X \) should exhibit a +3 valency. This is unusual because elements commonly combine with chlorine as \( XCl \) or \( XCl_2 \), etc., aligning with common valencies. Hence, \( X_2Cl_3 \) is likely incorrect.
2. X_2O_3: Oxygen generally has a valency of -2. For \( X_2O_3 \) to be valid, element \( X \) would need a +3 valency, which can occur in elements like aluminum (\( Al_2O_3 \)). Thus, this formula is correct for certain elements.
3. X_2(SO_4)_3: Sulfate \((SO_4)\) has a valency of -2. Therefore, three \((SO_4)\) ions would require a +6 total charge, which two \( X \) atoms could provide if each had a +3 valency. This compound is chemically plausible for elements that can exhibit a +3 oxidation state.
4. XPO_4: Phosphate \((PO_4^{3-})\) has a valency of -3. For this compound to be valid, element \( X \) would need a +3 valency, which is standard in chemistry, making \( XPO_4 \) correct for certain elements.

Based on typical valency rules and the common chemical structures of elements, the formula \( X_2Cl_3 \) is chemically incorrect as it does not correspond to a standard oxidation state for compound formation given the provided options. Thus, the incorrect formula is \( X_2Cl_3 \).