Not yet answered What is the correct name of the compound KSCN? Select one: A. Potassium sulfur cyanide B. Potassium cyanate C. Potassium thiocyanate D. Potassium cyanide
The Correct Answer and Explanation is:
The correct answer is: C. Potassium thiocyanate
Explanation:
The compound KSCN consists of the elements potassium (K) and the polyatomic ion SCN⁻, which is called the thiocyanate ion.
Breaking down the name:
- K is the chemical symbol for potassium, a Group 1 alkali metal. When naming compounds containing potassium, the name “potassium” remains unchanged in the compound name.
- SCN⁻ is the thiocyanate ion. It is a polyatomic ion made of sulfur (S), carbon (C), and nitrogen (N). Its structure can be written in two common resonance forms: S–C≡N⁻ and ⁻S≡C–N. In either case, it contains both sulfur and nitrogen atoms bonded to carbon. This differentiates it from similar ions like cyanate (OCN⁻) and cyanide (CN⁻).
Why not the other choices?
- A. Potassium sulfur cyanide: This name is incorrect and not standard in chemical nomenclature. There is no recognized ion called “sulfur cyanide.” It seems to be a misinterpretation of thiocyanate.
- B. Potassium cyanate: Cyanate has the formula OCN⁻, not SCN⁻. It contains oxygen instead of sulfur.
- D. Potassium cyanide: Cyanide is CN⁻, lacking sulfur. This would make the compound KCN, not KSCN.
Summary:
The ion SCN⁻ is called thiocyanate because “thio” indicates the presence of sulfur in place of an oxygen atom, as compared to the cyanate ion (OCN⁻). Therefore, the correct name for KSCN is potassium thiocyanate, a compound often used in analytical chemistry and coordination chemistry.
Correct answer: C. Potassium thiocyanate.
