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Use the periodic table to answer the question.

An illustration shows the periodic table of elements with elements arranged in increasing order of atomic number in 18 columns (groups) and 7 rows (periods). The electronegativity of elements increases from left to right, across a period. The hydrogen on the left is included in group with medium electronegativity. Also, fluorine is shown as element with highest electronegativity.

Based on patterns in the periodic table, which list shows the acids in order from strongest to weakest?

(1 point)
Responses

HCl, PH3, H2S
HCl, PH 3 , H 2 S

PH3, H2S, HCl
PH 3 , H 2 S, HCl

H2S, PH3, HCl
H 2 S, PH 3 , HCl

HCl, H2S, PH3

1 answer

To determine the order of acids from strongest to weakest, we can look at the electronegativity of the elements involved and how that affects the strength of the acids.

  1. HCl (hydrochloric acid): HCl is a strong acid because chlorine (Cl) is highly electronegative. It stabilizes the negative charge on the chloride ion (Cl⁻), making it more willing to donate a proton (H⁺).

  2. H₂S (hydrosulfuric acid): H₂S is a weak acid compared to hydrochloric acid. Sulfur (S) is less electronegative than chlorine, which means it doesn't stabilize the negative charge as effectively as Cl does when H⁺ is lost, making H₂S a weaker acid than HCl.

  3. PH₃ (phosphine): PH₃ is not typically considered an acid in aqueous solution and does not donate protons readily. Therefore, it is weaker than both HCl and H₂S.

Based on this analysis, the strongest to weakest order of acids is:

HCl > H₂S > PH₃

Thus, the correct response is:

HCl, H2S, PH3