= Solution
The strong $1810\,\mathrm{cm^{-1}}$ band is an <acyl chloride> <carbonyl stretching vibration>. Compared with an <ester>, donation from a <chlorine> <lone pair> into the <carbonyl> <antibonding molecular orbital> is relatively ineffective, while <chlorine>'s <inductive effect> withdraws <electron> density. The resulting stronger effective <carbonyl> force constant places the absorption above an ordinary saturated <ketone> band. Bond polarity alone is not a universal quantitative frequency rule.
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