. Name the following compound, BrF5 a. Bromine pentafluoride b. Bromine fluoride c. Bromine (IV) fluoride d. Monobromine pentafluoride 10. Avron was conducting his science fair project when he came across a bottle of acid whose label read, “HSCN.� What is the name of the acid that is contained within the bottle? a. Hydrocyanic acid b. Hydrothiocyanic acid c. Thiocyanic acid d. This acid does not exist 11. What is the chemical formula for copper (II) hydroxide 9. Name the following compound, BrF5 a. Bromine pentafluoride b. Bromine fluoride c. Bromine (IV) fluoride d. Monobromine pentafluoride 10. Avron was conducting his science fair project when he came across a bottle of acid whose label read, “HSCN.� What is the name of the acid that is contained within the bottle? a. Hydrocyanic acid b. Hydrothiocyanic acid c. Thiocyanic acid d. This acid does not exist 11. What is the chemical formula for copper (II) hydroxide? a. Cu2(OH) b. CuOH c. CuOH2 d. Cu(OH)2
The Correct Answer and Explanation is:
9. Name the following compound, BrF₅
Correct answer: a. Bromine pentafluoride
Explanation:
BrF₅ is a binary molecular compound consisting of a nonmetal (bromine) and another nonmetal (fluorine). The naming rules for such compounds involve using Greek prefixes to denote the number of atoms of each element and naming the more electronegative element (fluorine) last with the “-ide” suffix. “Br” is bromine and “F” is fluorine, with five fluorine atoms. Therefore, the correct name is bromine pentafluoride.
- Option b (“bromine fluoride”) is incomplete because it doesn’t indicate the number of fluorine atoms.
- Option c (“bromine (IV) fluoride”) uses ionic nomenclature, which is not appropriate for this covalent compound.
- Option d (“monobromine pentafluoride”) is incorrect because the prefix “mono-” is generally omitted for the first element when there is only one atom.
10. What is the name of the acid HSCN?
Correct answer: b. Hydrothiocyanic acid
Explanation:
HSCN is the chemical formula for hydrothiocyanic acid. It is a derivative of thiocyanate (SCN⁻) and behaves similarly to hydrocyanic acid (HCN), but with a sulfur atom replacing the oxygen in the corresponding oxyacid family.
- Option a, hydrocyanic acid, refers to HCN, not HSCN.
- Option c, thiocyanic acid, would be a less systematic name and could confuse with isomers.
- Option d is incorrect because HSCN is a known and real compound.
11. What is the chemical formula for copper (II) hydroxide?
Correct answer: d. Cu(OH)₂
Explanation:
Copper (II) means copper has a +2 charge (Cu²⁺). Hydroxide (OH⁻) has a -1 charge. To balance the +2 charge from one Cu²⁺, two OH⁻ ions are needed:
Cu²⁺ + 2OH⁻ → Cu(OH)₂
- Option a, Cu₂(OH), suggests incorrect stoichiometry.
- Option b and c, CuOH and CuOH₂, don’t correctly represent the 2:1 ratio.
Therefore, the only correct formula is Cu(OH)₂, a blue solid base.
