Question

which types of halogen compounds are known to contribute to ozone depletion?
a) salts
b) oxides
c) alkali metals
d) chlorofluorocarbons
question 11 (5 points)
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scandium forms the ion sc³+. how many bromite ions could bond with sc³+, and what would be the chemical formula?
a) 2 bromite ions, sc₂(bro₂)₂
b) 2 bromite ions, sc(bro₄)₃
c) 3 bromite ions, sc(bro₄)₂

Explanation:

• For the first question: Chlorofluorocarbons (CFCs) are halogen - containing compounds. When they reach the stratosphere, ultraviolet radiation breaks them down, releasing chlorine atoms. Chlorine atoms act as catalysts in the destruction of ozone ($O_3$) molecules. Salts (e.g., NaCl) are generally stable and do not contribute to ozone depletion. Oxides (e.g., $CO_2$) do not have the halogen - related reactivity for ozone depletion. Alkali metals (e.g., Na) are not halogen - containing compounds relevant to ozone depletion.
• For the second question: The bromite ion is $BrO_2^{-}$. Let the number of bromite ions be \(x\). For a neutral compound, using the charge balance principle (the sum of positive and negative charges is zero). The charge on \(Sc^{3 +}\) is \(+ 3\) and the charge on each \(BrO_2^{-}\) is \(-1\). So, \(+3+x\times(- 1)=0\), which gives \(x = 3\). The chemical formula is formed by balancing the charges. One \(Sc^{3+}\) ion and three \(BrO_2^{-}\) ions will form \(Sc(BrO_2)_3\). But if we assume a wrong ion consideration (if we wrongly take it as a similar - looking perbromate - like wrong - ion - based calculation, which is not correct for bromite), but based on charge balance:
• Option A: For \(Sc_2(BrO_2)_2\), the charge balance is \(2\times(+3)+2\times(-1)=+6 - 2=+4

eq0\)

• Option B: \(BrO_4^{-}\) is the perbromate ion, not the bromite ion (\(BrO_2^{-}\))
• Option C: The formula \(Sc(BrO_4)_2\) has wrong ion (should be \(BrO_2^{-}\)) and wrong charge balance (\(+3 + 2\times(-1)=+1

eq0\))

Answer:

• First question: D. Chlorofluorocarbons
• Second question: None of the options are correct. The correct answer is 3 bromite ions (\(BrO_2^{-}\)) and the formula \(Sc(BrO_2)_3\)