Chapter 4, Problem 6STP

Interpretation Introduction

Interpretation: Correct name of the metal oxide needs to be determined.

Concept introduction: Binary covalent compounds like ${\text{Fe}}_2{\text{O}}_3$ is type-II.

Rules for naming these compounds:

• Name of metal cation is written as name of element followed by charge carried by it in roman numerals in bracket.
• Name of anion is written using root name and adding ‘ide’ to it.
• Writing these names in the same sequence gives the name of compound.

Answer to Problem 6STP

B is correct option.

Explanation of Solution

Since Fe is leftmost name starts from iron. Fe is in +3 oxidation state so in bracket III is put. Since oxygen is second element it is treated as monatomic anion and name ends with oxide.

Complete name is iron (III) oxide.

Conclusion

In option A and D while naming charge of iron is not mentioned. Hence, they are incorrect.

In option C charge of the iron mentioned is $+2$ while actually iron is in $+3$ oxidation state. Hence, it is also incorrect.