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Which is most acidic in its aqueous solution? a)FeCl3 b)AlCl3 c)NiCl3 d)BeCl2

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To determine which compound is most acidic in its aqueous solution, we need to compare the acidity constants or strengths of the acids formed when these compounds dissolve in water. The greater the acidity constant (or lower pKa value), the stronger the acid.

a) FeCl3 (Iron(III) chloride) is formed by dissolving iron(III) ions (Fe3+) in water. The iron(III) ion does not give off protons in water, so it does not form a strong acid. It is not a strong acid in an aqueous solution.

b) AlCl3 (Aluminum chloride) is formed by dissolving aluminum ions (Al3+) in water. The aluminum ion does not give off protons in water, so it does not form a strong acid. It is not a strong acid in an aqueous solution.

c) NiCl3 (Nickel(III) chloride) is formed by dissolving nickel(III) ions (Ni3+) in water. The nickel(III) ion does not give off protons in water, so it does not form a strong acid. It is not a strong acid in an aqueous solution.

d) BeCl2 (Beryllium chloride) is formed by dissolving beryllium ions (Be2+) in water. Beryllium ion is a small cation with a high charge density, and it is highly polarizing. It reacts with water to form a strong acid, beryllium hydroxide (Be(OH)2), which then partially dissociates to form hydronium ions (H3O+). Therefore, BeCl2 is the most acidic in its aqueous solution among the given options.

Thus, the most acidic compound in its aqueous solution is d) BeCl2.

To determine which compound is the most acidic in its aqueous solution, we need to analyze the nature of the metals and their corresponding cations.

In this case, we have the following compounds:
a) FeCl3 (Iron(III) chloride)
b) AlCl3 (Aluminum chloride)
c) NiCl3 (Nickel(III) chloride)
d) BeCl2 (Beryllium chloride)

To assess the acid strength, we should consider the ability of the metal cations to donate protons (H+ ions) in water.

First, let's examine the trends relating to acid strength for these metal cations:

1. Alkali and alkaline earth metals (e.g., sodium, magnesium) tend to form weakly acidic solutions.
2. Transition metals (e.g., iron, nickel) usually form moderately acidic solutions.
3. Non-metals (e.g., beryllium) tend to form strongly acidic solutions.

Based on these trends, we can see that beryllium (Be) is a non-metal, and its associated compound, BeCl2, is expected to form the most acidic solution among the given options.

Therefore, the answer is d) BeCl2.

Finding Ka values for these salts is difficult. Intuitively I would think AlCl3 would be more acidic; however, I found Ka for FeCl3 = 2E-3 and for AlCl3 = 1.2E-5. From that information FeCl3 is the stronger. I could find no information about BeCl2 or NiCl3. Sorry I can't be more definite. If you have Ka values for all of these hydrated salts, the strongest acid will be the one with the largest Ka value.