To determine which pair of atoms has the greatest polarity, we need to calculate the difference in electronegativity between each pair of atoms.
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A. Al – Si:
- Al (1.61) - Si (1.9) = |1.61 - 1.9| = 0.29
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B. S - Cl:
- S (2.58) - Cl (3.16) = |2.58 - 3.16| = 0.58
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C. N - H:
- N (3.04) - H (2.2) = |3.04 - 2.2| = 0.84
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D. C - N:
- C (2.55) - N (3.04) = |2.55 - 3.04| = 0.49
Now we compare the absolute differences:
- Al - Si: 0.29
- S - Cl: 0.58
- N - H: 0.84
- C - N: 0.49
The pair with the greatest difference in electronegativity is N – H (0.84).
Thus, the answer is C. N – H.